more OpenGL error checking in OGLTrans

Change-Id: I7eff84d18be92423b3d8616162bfaf5be5203a9d
no need to make these variables public

Change-Id: I9b57d6811252c75186e03ed6928bd8829fa0307c
improve readability

Change-Id: I7a8791c661cbd3c602c0d12d228b63ffc416a96c
use constructor initializer list

Change-Id: I0bb1345f05dbd835e3f7debc66a824ccf44ef88b
basegfx -> glm in OGLTrans

Change-Id: I3f3002d975f3ee2732c5e132b3b67531356aad5c