Add the missing call to link_libraries() from my last commit

I dun goofed with the SOIL update. This fixes it.
Merge pull request #23 from HACKhalo2/patch-1

Add the missing call to link_libraries() from my last commit
Fixed an OOB issue with GLMesh::MeshGroup_ElementCount

The current implementation would fail if there are no mesh groups.
Removed some unnecessary getInstance calls

Now the return from FactorySystem::getInstance is saved and reused.
Added UV buffer to GLMesh
debug option directly added to makefile