Bug 662744 - remove obsolete background image rules, r=dao

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extra : rebase_source : 02de983ca70eb349cfc31adf4af3ac95df8731a0
Bug 1004410 - allow running mochitests against an arbitrary binary, r=jmaher

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extra : rebase_source : ba7e34aaffe2dd845b8717a34dc27c7f59983534