#42: Retrieve informations once and use them in the whole program

Fix #42 (closed)

changed target branch from master to dev

changed title from 42 data init to #42: Retrieve informations once and use them in the whole program

changed the description

added 22 commits

• 6a358de4...c7675605 - 17 commits from branch dev
• 141e07e7 - [enh] #42 (closed): retrieve head_block and currency params at the beginning.
• db54440f - [enh] #42 (closed): head_block and params: retrieve once and use in the program.
• 24ef1687 - [enh] #42 (closed): retrieve head_block and currency params at the beginning.
• 82b20e7e - [mod] return boolean values from check_port().
• b3fdc101 - [mod] give best_node() boolean values.

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