Merge some Bitcoin code as preliminary step to support coin control features.

New data structures:
-CPubKey
-CKeyID
-CScriptID
-CTxDestination
Add coin control features (experimental, don't use that with real coins yet !).
Fix transaction list bug.
Fix bug causing the custom change address to be ignored in coin control.
add createmultisig RPC

add createmultisig RPC call
Add signed message verification feature.
Update french locale.

Add translation for new menu entry (unlock wallet for minting).
Fix typos.
Add french translation to coin control features.
Add french translation to signed message verification feature.
Fix createmultisig RPC.
Merge pull request #19 from glv2/peerunity-rc

Coin control + createmultisig + french translations