Take the operation id of the bank
Create an id for calls
do not cry if an object in not support to be filled by a backend
remove unused imports
New certificat
More robust currency guessing

This allows to parse PayPal balances which includes both symbol and letters, for
instance "$ 42,00 USD".
Also, it does not require adding any new symbols to the regular
expression.
It might break modules, though numerous cases were tested.
Add basic PayPal module

Limitations for now:
* Only French-style (UUU,CC and not UUU.CC) balances; the choice is not left up to the user so
  it's hard to test
* No history (should be easy to add)