Removed TextureContent._bitmap.
It was only used in two locations:
1. Resizing a texture (for the resize-pow-two condition in TextureProcessor). It allocates a bitmap and then disposes it when done with this operation.
2. Font processor works with bitmaps, but rather than assuming there is one on the texturecontent up front, it just creates one.

This means that everyone else in the pipeline can rely on TextureContent.GetData/SetData always being what you expect it to be instead of being mysteriously out of sync with a _bitmap that your custom processor doesn't know about or have access to.
Allow loading textures directly from system images (UIImage, NSImage) on iOS and Mac, avoiding having to turn the image to stream and then read it from stream
Update Threading from Cocos2DXNA to ensure correct WP8 FromStream behaviour
Tidied up threading for WP
Add support for StencilWriteMask to OpenGL backend
Merge pull request #2640 from prollin/patch-2

Add support for StencilWriteMask to OpenGL backend
Merge pull request #2638 from Nezz/iosfromstream

Texture2D.FromStream on iOS and Mac
Merge pull request #2639 from Nezz/threadingupdate

Update Threading
We now account for time stamp changes in the source file.
Merge pull request #2642 from SickheadGames/sourcetime

MGCB Source DateTime
The context menus for items and folders are now defined in the WinForms designer.
Reusing the existing add/remove item logic in the context menus.
Added per-item build/rebuild/clean options.
Further context menu cleanup.
We can now save temporary partial projects.
Added support for rebuilding individual content items.
When game is re-activated the mouse button state will reset itself to actual values.
Merge pull request #2644 from SickheadGames/FormMouseButton

MouseState.Button out of date
Fixed byte order used for colorkey and premultipled processing.
Fixing Mac build.
Merge pull request #2643 from SickheadGames/pipeline6

Pipeline Tool Item Rebuilds
Removed commented out code.