Splitted messages into projects by FIX version

Updated .gitignore
Fixed messages generating when a field has its message name

Happens in FIX50SP1 & FIX50SP2 with the message/field SecurityStatus
Changed the DefaultMessageFactory to load FIX versions dynamically.

Its new function is to be MessageFactory factory.
Updated projects references to the split messages dlls
Fixed acceptance test FIX50SP1 and FIX50SP2 tests