Update *.csproj to .net 4.0.
Add VS2010 solution.
Fix default.build for Boo.Lang.PatternMatching.
Remove AllowPartiallyTrustedCallers for .net 4.0.
Fix type modifiers for default ctor.
Add OutputDirectoryGenerator to CompilerParameters.
Replace Dictionary with ConcurrentDictionary for all the cache.
Fix generating assembly version into file.
Update AbstractInterpreter to make more methods as virtual.
Reduce the errors in output of booc.