Don't stop the Stopwatch until we are ready to start the run loop. Previously we'd be accumulating update time while the game loaded, which would lead to _maxElapsedTime worth of updates before the first draw call was made.
Redo the IsRunningSlowly calculation to use a method that closer resembles XNA behaviour. We now count how many lost frames we've had and use that as the trigger.

Fixes #2595
Merge pull request #2607 from danzel/isrunningslowly

Redo the IsRunningSlowly calculation
Merge pull request #2606 from danzel/gamestart-update-spam

Fix burst of Game.Update calls at the start of the game
Fix referencing aliasing with new Protobuild
Fix build error under Windows
Merge pull request #2610 from hach-que/alias-fix

Fix referencing aliasing with new Protobuild
Fixed Game.Exit() crash on WinGL and Linux platforms.

We must not call Game.Tick() after Game.Exit().
Fixes issue #2605.
First implementation of ReflectiveWriter.
Added EnumWriter support.
Merge pull request #2614 from thefiddler/runloopfix

Fixed Game.Exit() crash on WinGL and Linux platforms.
Fixed tabs.
Merge pull request #2616 from SickheadGames/reflective_writer

ReflectiveWriter
Get platforms that return false in BeforeRun working again (Just Android...) refs #2615
Merge pull request #2617 from danzel/fix-android

Get android working again
First rough skeleton of IntermediateSerializer classes.
Added some of the implementation from the XmlImporter work.
Removed unused usings.
Merge pull request #2621 from SickheadGames/intermediate

IntermediateSerializer Skeleton
Fixed Texture2D.GetData on DirectX platforms
Added support for the element count parameter
This should fix GetData for Texture3D.Directx