Removed old files

Signing on the way. There is a bug becuse of ucoin API using keyword "self", and it's conflicting with python self keyword.

Wallet content now show available sources, while Transactions sent and received will display latest transactions sent and received

We can export and import accounts

Configuring account reworking
Some bugs fixed

Account now has Wallets and Communities
Wallets are now managing the network side of ucoin
A community doesnt depend anymore on a wallet
A wallet knows what community it is part of thanks to currency name

Refactoring
Debugging

Configuring account : changing its name and the communities