VideoCommon: use the Light struct in XF memory
PixelShader: use the vertex const buffer for ppl
PixelShader: remove the duplicated ppl constants
LightingShader: hard code const variable
Make the common "Failed to enumerate outputs" message much more useful.

Now it includes its most common cause, a simply-worded solution, and an exclamation point.
Abort loading a save state if emulation isn't running.
Merge pull request #520 from pauldacheez/enumerate-outputs-harder

Make the common "Failed to enumerate outputs" message much more useful.
Merge pull request #523 from RachelBryk/uninitialized-load-state

Abort loading a save state if emulation isn't running.
Merge pull request #439 from degasus/lighting-fix

Lighting cleanup