Fix compilation on OSX 10.10
Closes #1646
Fix linking on OSX
Merge pull request #1652 from tobbi/fix_mac_compilation

Fix compilation on OSX 10.10
Fix rtt crash
Add a check for instance buffer overflow
Merge pull request #1653 from tobbi/fix_mac_linking

Fix linking on OSX
Use exp algorithm for the gaussian blur
Implement Exponential Shadow map
Add trilinear + anisotropic on shadows
Use MSAA for shadowmap
Try to fix incomplete fbo attachement
Revert "Use MSAA for shadowmap"

This reverts commit fce9fe4385aa488a6f02814790022828d5e8f8bf.

Conflicts:
	src/graphics/render_geometry.cpp
	src/graphics/rtts.cpp
Implement shadow blur
Fix textureview
Fix moiré pattern