Bug 1053080 - Improve mozbuild.util.memoize and add memoized_property. r=gps
Bug 1053085 part 1 - Rely on the config environment for TOPSRCDIR and TOPOBJDIR within frontend code. r=gps
Bug 1053085 part 2 - Move config environment fiddling out of MozbuildSandbox initialization. r=gps
Bug 1053097 - Delay the gathering of python dependencies for the build backend. r=gps
Bug 1053140 part 1 - Add a default_dict-like container, with a default_factory taking the key as argument. r=gps
Bug 1053140 part 2 - Add a test for exported variable override. r=gps
Bug 1053140 part 3 - Separate out sandbox infrastructure from moz.build variables storage. r=gps

--HG--
rename : python/mozbuild/mozbuild/frontend/sandbox_symbols.py => python/mozbuild/mozbuild/frontend/context.py
rename : python/mozbuild/mozbuild/test/frontend/test_sandbox_symbols.py => python/mozbuild/mozbuild/test/frontend/test_context.py