Render pipeline efficency update

[rcmaniac25]

Investigate and test efficiency updates that are transparent to developer.

• Async graphics loading (think Doom 3: BFG)
• Material handling (if multi-part Model, but one material/RenderState/Pass/Effect, then it should iterate through passes THEN parts. Currently it defaults other way [iterates through parts, and keeps rebinding the passes])
• State changes (Make sure state-switching doesn't happen to already bound elements [this way dev-done grouping works properly])

Sources:

• Approaching zero driver overhead (Steam DevDays)
• Beyond Porting: How Modern OpenGL Can Radically Reduce Driver Overhead (This starts at the list of state changes, ordered by cost of change)
• Approaching Zero Driver Overhead in OpenGL (GDC 2014)