Major release : v0.8.1

Hello everyone,

I've just released the version 0.8.1. As annouced before, all major new features are paid. v0.8.1 features the use of several currencies :

• Define your default currency
• Set the exchange rates with the other currencies
• Define the default currency for the expenses of a piggy
• Define the currency when creating/modifying an expense or a payback

I'm still listening to your comments and suggestions !

Regards.