Bug 917593 - Don't assert for zero-length strings. r=Waldo
Bug 921399 - Fix memory leak. r=gabor
Bug 920553 - Hoist GlobalProperties out of SandboxOptions. r=gabor
Bug 920553 - Make GlobalProperties::Parse follow JSAPI exception convention. r=gabor

Anything that returns false should set an exception unless either (a) the
failure resulted from another JSAPI call that would have set an exception or
(b) the failure indicates OOM.
Bug 920553 - Introduce Cu.importGlobalProperties API. r=gabor