Cleanup VertexBuffer ifdefs
Copying out platform versions of VertexBuffer.
Deduplicating platform code in VertexBuffer
Extracted platform methods from IndexBuffer.
Platform copy for IndexBuffer.
IndexBuffer platform code split.
Fix for PSM
Fix index buffer usings for GLES
Fix ifdef for GLES
Fixed measure string to return correct width if spacing is used
Merge pull request #2272 from Nezz/measurestringfix

Fixed measure string to return correct width if spacing is used
Merge branch 'develop' of git://github.com/mono/MonoGame into monogame-sdl2
Merge pull request #2259 from SickheadGames/VBIBSplit

Split VertexBuffer/IndexBuffer on a per-API basis
Merge back from develop, reject everything again...
Rebrand and clean up Threading.cs, adjust related files as needed.
Docfix
Move some things around in the SDL2 Platform/Window
Fix transition to borderless SDL2 window
Unused file from MonoGame
Remove another GenerateGL method