Add a few missing equality operators to Input structs.

Add equality operators and Object.Equals() overrides to the
GamePadButtons, GamePadDPad, GamePadThumbSticks, and GamePadTriggers
structs in the MonoGame.Framework.Input namespace.
Make SoundEffect.Play not throw an exception on iOS if it fails to play, return false instead as we are meant to.
Implement TryPlay on other platforms.
Fix playing multiple music tracks, previously when the first one finished we'd play the second which would reset the queue.
Update Libs to SharpDX 2.5.
Merge pull request #2058 from danzel/fix-mediaplayer-queue

Fix playing multiple music tracks from a collection
Merge pull request #2056 from danzel/fix-ios-audio-crash

Fix SoundEffect.Play return value and iOS/Mac crash
Merge pull request #2046 from PrecisionMojo/_pm/add-missing-input-equality

Add a few missing equality operators to Input structs.
Merge pull request #2096 from KonajuGames/sharpdx-2.5

Update Libs to SharpDX 2.5.
Merge remote-tracking branch 'upstream/develop' into develop