Only build engine and extract with pch.  Fix transitive header dependencies.
Only build engine and extract with pch.  Fix transitive header dependencies.

grit-engine/grit-engine,grit-engine/grit-engine,sparkprime/grit-engine,grit-engine/grit-engine,grit-engine/grit-engine,sparkprime/grit-engine,sparkprime/grit-engine,sparkprime/grit-engine