Removed PreferredInterfaceOrientationForPresentation()

Causes bugs with PresentViewController to be described in pull request
Fixes orientation changes for Android Tablets.
Fix for orientation when Activity closed.

Android Activity still lives, so the OnOrientationChanged event is still
executed, even thou AndroidGameActivity.Game is null. This commit fixes
this issue. Since it's a very small fix and related to the same method
of the first commit, I just added another commit to the same PR.
GamePad now throttles checking disconnected controllers.
Removed uses of extremely slow Enum.HasFlag() in GamePad.
GamePad now throws InvalidOperationException when called with a bad player index.
Removed excessive function call nesting in GamePad.
Fixed GamePadCapabilities.HasDPadRightButton which was incorrectly testing the left dpad button state.
Merge pull request #1936 from jonathanpeppers/develop

Removed PreferredInterfaceOrientationForPresentation() for iOS
Merge pull request #2000 from SickheadGames/xinput

GamePad XInput Performance
Merge pull request #1987 from azchohfi/androidOrientationFixForTablets

Fixes orientation changes for Android Tablets.
Merge remote-tracking branch 'remotes/upstream/develop' into develop