Removed redudant supertypes.
Fixed TryGetValue().
MGCB links against MonoGame now and not MS XNA.
ContentCompiler.Compile() is now internal.
Fixed WriteXnb to use ContentCompiler directly.
Removed the MSBuild tasks from the pipeline project.
We now throw PipelineException when we cannot find or execute importers or processors.
We now print errors to the console in ContentProject.Build().
Merge branch 'develop3d' into mgcb
Pipeline project now references Windows and not WindowsGL.
Removed MSBuild assembly references.
Deleted MSBuild Tasks... we won't be using them.
Merge pull request #1223 from SickheadGames/mgcb

MGCB Improvements