add doc + xsd
add Credit Transfert Transaction + update other messages to make it work
credit transfert needs execution date instead of collection date
replace pain.001.001.02 by pain.001.001.03
automatic execution/colltion date
fix unit tests
Merge pull request #19 from sbouba/dev-feat-sepa-credit-transfer

[RFR] Sepa Credit Transfer, I will improve your contribution