libsass 3.0.2

Massive update for libsass. Has been merged into the core Sass
repository on Github now, hence the homepage and url shifts.

Closes #34296.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
libsass: update 3.0.2 bottle.
gcc: sandbox within series release number only

Fixes #33948.
gcc: update 4.9.2_1 bottle.