Blender Git Loki

Fix T41596 GLSL error on ATIs after clipping workaround commit.

This was a little difficult to track down, basically it was a missing
escape sequence that only manifested itself when GPU did not support
bicubic filtering.

Extra:

* Fix memory leaks when an error occurs in shader compilation
* Display full shader when a compilation error occurs. Makes it easier
to diagnose if problem is caused by a syntax or compatibility error.