[Requirement #12666] - Mac (OSX) support
- Updated log4net to 1.2.13.0, which now has an official .NET 4.0 version, so we don't have to build it ourselves.
- Also checking in the other binary versions, including the one for Mono and older versions of the .NET Framework.
[Requirement #12666] - Mac (OSX) support

Rebuild NHibernate against new version of log4net.