Finalize Filter Branch

[Shiandow]

With these commits the filter branch should be almost ready for release.

Although at the moment AudioFilters fail literally silently (e.g. when using Reclock with an incompatible audio renderer), we might want to fix that. Fixed.

Everything else should work though, and this should also bring the filter branch up to date with the current master branch.

These commits also change quite a few details of the framework on top of the changes from the filter branch. In short:

• Centralized method for handling hotkeys.
• Separation between TextureFilter and RenderChain namespaces, with extension methods to accomplish most common tasks without needing the TextureFilter namespace.
• New method for handling shader constants (not really used yet, but should be soon).
• Various fixes, and refactorings.

And some updates for SuperRes/SuperChromaRes/SSIM, but those are still a bit of a work in progress, with a proper release coming soon.

[Shiandow]

Reclock output is still garbled at some times, usually when switching to it during playback (if it's on from the start it doesn't seem to happen as much), not sure what's happening there, maybe the audio renderer is messing things up.