Merge pull request #432 from nyue/master

Added guard against git_tag variable for non-git source tree tarball
fixed typos and formatting.
improved log output when running unit tests from appleseed.cli.
updated readme.
Fixed broken OSL build.
Merge pull request #433 from est77/master

Fixed broken OSL build.
texture transforms were not preserved across edits.

fixed issue #435.
Fixed weird compile error for vintage gcc version.
adjusted step sizes for integer inputs in Render Settings dialog.
Merge branch 'master' of github.com:appleseedhq/appleseed
small code tweak.
emit a warning if an object instance has alpha transparency on one side but not on the other.

several refactorings and code movements.
added a comment.
Added simple glass test scene.
Merge pull request #444 from est77/master

More OSL test scenes
updated license notice.
removed old jupiter jazz logos.
Fixed bug when using refraction closure from OSL.
Merge pull request #445 from est77/master

Fixed bug when using refraction closure from OSL.
removed black variants of appleseed logos.