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.
this fixes #386

Removes unused Tools->Settings menu item, until decent setting dialog would be implemented
Merge pull request #388 from klokik/master

this fixes #386
Merge pull request #381 from liiza/master

Added RGBA label
Merge branch 'master' of https://github.com/appleseedhq/appleseed
minimize dock-widgets in a statusbar

User has option of minimizing dock widgets. Also he can
enter fullscreen mode by going to the View menu or by
pressing F11. When exiting fullscreen mode the state will
be the one before the fullscreen. If some widgets were
hidden before they will remain that way after.

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
fixed issue 259
added mechanism to find the appleseed::studio::RenderTab associated to a given tab.
some minor fixes