Prevent referencing non-existent bones.
MonoGame.Framework GUIDs reverted to previous state with the exception of:

Angle, new GUID generated as it was using the same as the Windows platform
WindowsPhone, new GUID generated as it was using the same as the Windows platform

Fix requested as part of #2560
Added missing effect content writers.
Replaced GUID's in MonoGame.Framework.Net.definition
Modified as per @tomspillman request
Updated WindowsGL GUID
Several fixes/improvements to XACT.
Create tools.md
Create 2mgfx.md
Update tools.md
Create mgcb.md
Update mgcb.md
Added tool docs.
Update 2mgfx.md
Update 2mgfx.md
Update 2mgfx.md
Merge pull request #2563 from SickheadGames/XACT_Fixes

Several fixes/improvements to XACT and SoundEngine behavior.
Merge pull request #2561 from DDReaper/develop_ProjectGuidRevert

MonoGame.Framework GUIDs reverted to previous state as per #2560 request
Update GameServiceContainer.cs

Added generic overloads for AddService() and GetService().
Simpler and cleaner to use, and with the generic GetService() there's also need to cast/unbox from object.
Added PS4 note.