Handle pubkey's checksum in the tx code

The following discussion from !132 (merged) should be addressed:

• @matograine started a discussion: (+3 comments)

  Seems like there is a bug in the tx.py module. (I use the checksum example given by Tortue)

  silkaj --gtest tx -r Hvrm4fZQWQ2M26wNczZcijce7cB8XQno2NPTwf5MovPa:5XP -a 100
  Please enter your Scrypt Salt (Secret identifier): 
  Please enter your Scrypt password (masked): 
  ╒════════════════════════════════════════════╤══════════════════════════════════════════════════╕
  │ pubkey's balance before tx (unit|relative) │ 96678.75 ĞTest | 9.6756 UD ĞTest                 │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ total transaction amount (unit|relative)   │ 100.0 ĞTest | 0.01 UD ĞTest                      │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ pubkey's balance after tx (unit|relative)  │ 96578.75 ĞTest | 9.6656 UD ĞTest                 │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ from (pubkey)                              │ AhRMHUxMPXSeG7qXZrE6qCdjwK9p2bu5Eqei7xAWVEDK     │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ to (pubkey)                                │ Hvrm4fZQWQ2M26wNczZcijce7cB8XQno2NPTwf5MovPa:5XP │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ amount (unit|relative)                     │ 100.0 ĞTest | 0.01 UD ĞTest                      │
  ├────────────────────────────────────────────┼──────────────────────────────────────────────────┤
  │ comment                                    │                                                  │
  ╘════════════════════════════════════════════╧══════════════════════════════════════════════════╛
  Do you confirm sending this transaction? [yes/no]: yes
  Generate Transaction:
     - From:    AhRMHUxMPXSeG7qXZrE6qCdjwK9p2bu5Eqei7xAWVEDK
     - To:      Hvrm4fZQWQ2M26wNczZcijce7cB8XQno2NPTwf5MovPa:5XP 
     - Amount:  100.0
     - Total:   100.0
  Traceback (most recent call last):
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/bin/silkaj", line 11, in <module>
      load_entry_point('silkaj', 'console_scripts', 'silkaj')()
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/click/core.py", line 764, in __call__
      return self.main(*args, **kwargs)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/click/core.py", line 717, in main
      rv = self.invoke(ctx)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/click/core.py", line 1137, in invoke
      return _process_result(sub_ctx.command.invoke(sub_ctx))
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/click/core.py", line 956, in invoke
      return ctx.invoke(self.callback, **ctx.params)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/click/core.py", line 555, in invoke
      return callback(*args, **kwargs)
    File "/mnt/DATA/Users/bob/Documents/Associatif/June/Developpement/dev-silkaj/silkaj-multi_output/silkaj/tools.py", line 70, in wrapper
      return loop.run_until_complete(f(*args, **kwargs))
    File "/usr/lib/python3.7/asyncio/base_events.py", line 584, in run_until_complete
      return future.result()
    File "/mnt/DATA/Users/bob/Documents/Associatif/June/Developpement/dev-silkaj/silkaj-multi_output/silkaj/tx.py", line 141, in send_transaction
      key, issuer_pubkey, tx_amounts, recipients, comment, outputbackchange,
    File "/mnt/DATA/Users/bob/Documents/Associatif/June/Developpement/dev-silkaj/silkaj-multi_output/silkaj/tx.py", line 301, in handle_intermediaries_transactions
      OutputbackChange,
    File "/mnt/DATA/Users/bob/Documents/Associatif/June/Developpement/dev-silkaj/silkaj-multi_output/silkaj/tx.py", line 339, in generate_and_send_transaction
      transaction.sign([key])
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/duniterpy/documents/document.py", line 84, in sign
      signing = base64.b64encode(key.signature(bytes(self.raw(), "ascii")))
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/duniterpy/documents/transaction.py", line 839, in raw
      doc += "{0}\n".format(o.inline())
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/duniterpy/documents/transaction.py", line 201, in inline
      self.amount, self.base, pypeg2.compose(self.condition, output.Condition)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/pypeg2/__init__.py", line 699, in compose
      return parser.compose(thing, grammar)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/pypeg2/__init__.py", line 1299, in compose
      return terminal_indent() + thing.compose(self, attr_of=attr_of)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/duniterpy/grammars/output.py", line 383, in compose
      left = parser.compose(self.left, grammar=grammar, attr_of=attr_of)
    File "/home/thomas/.cache/pypoetry/virtualenvs/silkaj-HKHTj0CI-py3.7/lib/python3.7/site-packages/pypeg2/__init__.py", line 1333, in compose
      + grammar.pattern)
  ValueError: '' does not match \w+
  ERROR:asyncio:Unclosed client session
  client_session: <aiohttp.client.ClientSession object at 0x7fc8c1496080>
  ERROR:asyncio:Unclosed connector
  connections: ['[(<aiohttp.client_proto.ResponseHandler object at 0x7fc8c14fbd48>, 83529.411582788)]']
  connector: <aiohttp.connector.TCPConnector object at 0x7fc8c1496048>