Bug 1013662 - Part 1: Add MOZ_IMPLICIT to Attributes.h; r=froydnj

--HG--
extra : rebase_source : 4654de918e6f73f40c34a19cfd1b457ba2c734f1
Bug 1013664 - Fix bad implicit conversion constructors in XPCOM; r=froydnj

--HG--
extra : rebase_source : e3260a536292175cb1ad23a53dfe9e3f4bb8ff10