Hook up Javascript implementations to JSAPI class

To enable this to work, developers need to modify the default index.htm generated by Protobuild to have:

        manifests: [
          "MonoGame.Framework",
          "JSILPort.exe"
        ],

This will cause the appropriate MonoGame libraries to load.
Merge pull request #2517 from hach-que/web-api-working

Hook up Javascript implementations to JSAPI class
Implement game tick for Web platform

This hooks up the game's update and render loop for the Web platform, using
window.setTimeout to drive the loop behaviour.

Currently it always renders red when the graphics device is cleared, but this
is temporary.
Include JSAPIAccess in project definition
Merge pull request #2519 from hach-que/web-tick

Implement game tick for Web platform
Merge pull request #2518 from SickheadGames/docs

Documentation Style Fixes
Update Assimp library.
Merge pull request #2526 from JamesLupiani/Assimp

Update Assimp library.
Implemented several methods necessary for copying between bitmaps. Note: only copying between two PixelBitmapContent<T> where T is the same type has been implemented.
Added missing implementation for BitmapContent.ToString()
GraphicsUtil.CompressTexture no longer throws an exception for non-pow2 dxt textures if the GraphicsProfile is HiDef (this matches original XNA behavior).
TextureProcessor tries to set its pixel data to _bitmap. Bitmap only exists if the texture was loaded by the TextureImporter and even in that situation the pixeldata was already setup.
Merge pull request #2527 from SickheadGames/SpriteSheetProcessorFixes

BitmapContent.Copy, PixelBitmapContent.CopyTo
Correctly set TouchCollection.IsConnected based on TouchPanelCapabilities.IsConnected (not that that is correct yet).

Fixes #2531
Windows TouchPanelCapabilities MaximumTouchCount/IsConnected detection.
Android TouchPanelCapabilities MaximumTouchCount/IsConnected detection. These are sort of wrong due to API limitations, 2 means 2-4, 5 means 5+
Tidy up licence and usings in this file
iOS maximumTouchCount support. Harded coded values as found on google.
Linux and Mac have no touch support for now.
Touch count support for windows phone and PSM. PSM is just made up for now.
Since I've touched almost every line in here, white space cleanup.
FreeImage.GetBitmap() doesn't support images that are >32bpp. The image is now converted if necessary.
Cleaning up unmanaged resources.