Bug 941083 - invalidate widget wrappers on createWidget calls, r=mconley

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extra : rebase_source : 60a2c6eb754d6c9c87fb5987fe5fbd39be2581a5
Bug 940632 - Fixup findbar scroll positioning code and remove some text zoom cruft. r=mbrubeck
Bug 936567 - Add proper support for apzc scale in browser binding utils, fixing up various ui element positioning issues with zoom. r=mbrubeck