Prevent referencing non-existent bones.
Added missing effect content writers.
Latest dependencies with CppSharp update.
Merge pull request #2573 from SickheadGames/cppsharp2

Dependencies Update
Emit multiple geoms per mesh instead of multiple meshes.
First pass material->effect processing.
A little more work on the model processor.
XmlImport now has PassThroughProcessor as its default processor (which matches xna) rather than (for some reason) ModelProcessor.
Remove everything from FileHelpers except NormalizeFilePathSeparators and DirectoryCreate. They would all only be used in one place.
Move CreateDirectory into StorageContainer, where it is used twice.
Whitespace and license since I just nuked most of this file.
Merge pull request #2575 from SickheadGames/XmlImporterDefaultProcessor

Fixed XmlImporter's DefaultProcessor
Fix build on not WINRT
Merge pull request #2576 from danzel/clean-filehelpers

Remove FileHelpers that are not needed
Yet more Model Processor progress.
Support for Byte4 vertex elements.
test

test
Fixed broken SoundEffectInstance.IsLooped on Android.
Merge pull request #2582 from nkast/test2

VertexDeclaration.FromType() fix
Merge pull request #2574 from Andreyul/android_sound_loop

Fixed broken SoundEffectInstance.IsLooped on Android.