New render state block API for Renderer
Use RenderState in scenegraph
Use RenderState in background, HS cloud, projectile, sfx, speedlines
RenderState in UI
RenderState in modelviewer

note, moved grid drawing a bit later so it clips into the model correctly
Remove old-gui ShipSpinnerWidget
Use RenderState in planet and star rendering
Use RenderState in most of the views
Merge remote-tracking branch 'origin/master' into statesets
Remove a couple of old-gui classes: FaceVideoLink and GuiGradient
Require RenderState passed to DrawTriangles and DrawPointSprites
Tombstone never cleared depth

Also don't bother restoring old ambient, it's set in intro anyway
RenderState in worldview
Remove blend/depth state change functions
Delete old shieldEffect, unused
Remove twoSided property from material, use cullMode in RenderState instead
DrawSurface now requires a RenderState
Wireframe mode remains in renderer

Difficult to implement with states as it's usually used as an override
Avoid redundant state changes at a high level
Don't use fixed function rendering for drawpoints/lines2D