Protect against the exception if the content list doesn't exist.
Added /quiet switch to MGCB.
Added new target file for compiling a .contentproj in VS using MGCB.
Merge pull request #1664 from SickheadGames/mgcb

MGCB Support For Content Projects
Merge branch 'develop' of github.com:jalf/MonoGame into develop
Added support for all remaining SurfaceFormat values in OpenGL
HalfVector2, HalfVector4, Rg32, Rgba64, Rgba1010102, Vector2, Vector4, HdrBlendable, NormalizedByte2, NormalizedByte4.
Merge pull request #1686 from slygamer/surface-formats

Added support for all remaining SurfaceFormat values in OpenGL
Merge remote-tracking branch 'upstream/develop' into develop