Added Oren-Nayar BxDF, closure.

        - Added Oren-Nayar BRDF, OSL closure.
Updated cmakefiles, OrenNayar.
Added OrenNayar test scenes.
Added OSL OrenNayar shaders.
Added Oren-Nayar OSL shaders.
Added Oren-Nayar OSL test case.
Registering Oren-Nayar to OSL.
Registering Oren-Nayar to OSL, fix typo.
Updated OSL test scene, cleanups.

        - Updated OSL test scenes for Oren-Nayar BxDF.
        - Removed unused variables, minor fixes and cleanups.
Merge branch 'master' of https://github.com/appleseedhq/appleseed into oren_nayar

Conflicts:
	sandbox/tests/test scenes/osl closures/01 - area light - ptne.appleseed
Added Oren-Nayar to BxDF test scene.
Formatting fixes.
Improved fixes for issue 259 with new icon for clear frame button
Moved MinimizeButton to separate file

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
Merge pull request #394 from marius-avram/B331-refactor

Moved MinimizeButton to separate file
Merge pull request #396 from liiza/bugfixing

Hide scrollbars on RGBA QTextEdit widget.
small code tweak.
minor cosmetic fixes for issue 259
minor code tweaks.
Merge pull request #393 from sriravic/issue259imp

Improved fixes for issue 259 with new icon for clear frame button