Bug 1022594 Part 1a Add a getLoopBoolPref function to the MozLoopAPI. r=mikedeboer

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rename : browser/components/loop/test/mochitest/browser_mozLoop_charPref.js => browser/components/loop/test/mochitest/browser_mozLoop_prefs.js
rename : browser/components/loop/test/xpcshell/test_loopservice_get_loop_char_pref.js => browser/components/loop/test/xpcshell/test_loopservice_loop_prefs.js