Bug 1013518 - include CSS linter test in mochitest-devtools, r=bgrins

--HG--
extra : rebase_source : 1bb0104e310d38c2b2265b351bda9230f306d28d
Bug 1014238 - don't break on invalid customization state, r=jaws

--HG--
extra : rebase_source : a803b73d7eda4ad38073f8d280324710666c16c7
Bug 1012750 - defineLazyModuleGetter should log failing URL if there was an error loading, r=mak