Bug 981281 - Ctrl+left/right arrow skips words with leading/trailing punctuation with layout.word_select.stop_at_punctuation=false. r=mats

test3/test4 are copies of test1/test2 tweaked for stop_at_punctuation=false.
Bug 981477 - Re-enable globally-disabled reftests on B2G that actually pass. r=ahal
Bug 997208 - Remove unnecessary nullptr checks before deleting in content/media. r=cajbir