Poc with lot of debug print()

round values from referential in informations_tab

Fix accept button in contact dialog not enabled when adding from context menu

- Fixed issue #55
- Fixed display of units in transactions tab
- Fixed an error when an account was not a member of a community

Conflicts:
	src/cutecoin/gui/currency_tab.py
	src/cutecoin/models/txhistory.py

Fix bug refresh_block

 Open a messagebox for better alerting user