Add `decode` command for event, message and constructor data decoding

Sergej Kostjucenko requested to merge ag-decode-cmd into master

Created by: agryaznov

As a response to user feature request (e.g. like in this StackExchange question):

  1. New command added which allows to decode data from contract events and messages
  2. Corresponding encoded values printing added to debug log (where there was lack of such)

Merge request reports