Write unit tests for the transaction command

Transaction is the most critical part of Silkaj. It should be covered with tests.

• simple tx
• intermediaries txs
• multi-output
• #235 (closed): one of amount, amountUD, allSources option should be specified
• many other small cases
• …

changed milestone to %0.8.0

mentioned in issue #235 (closed)

changed the description

added To Do label

removed To Do label

added To Do label

removed To Do label

changed milestone to %0.9.0

mentioned in commit 99bc94d1

mentioned in commit 09697aaa

mentioned in commit 397acea8

mentioned in commit a407ff13

mentioned in commit 1d8f8aac

mentioned in commit 62954d2a

mentioned in commit e22e607e

mentioned in commit 7f6a36ed

mentioned in commit 7745e315

mentioned in commit cf05116e

mentioned in commit 3b9c77c4