Vs2012 and cleanup

Add a root .gitignore. 

Remove C++ part from README. 

Add VS2012 SLN files (but holding off on targeting new .NET Framework for now). 

Remove extraneous Finalizers. In C#, Finalizers are not like C++ destructors. They're "last chance" pass after an object is GC'd, so it can clean up direct unmanaged resources. The VoltDB client doesn't use any unmanaged resources directly, so it doesn't need this code.