Bug 493701 - part 1: add nsTObserverArray::BackwardIterator; r=bzbarsky

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extra : rebase_source : cf37f9cf8ee8a4198741eea69d0fcedef64053fc
Bug 493701 - part2: Use TObserverArray for DocLoader Listeners; r=bzbarsky
* * *
Bug 493701 - part 3: add and use a BackwardIterator::Remove method; r=bzbarsky

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extra : rebase_source : c2d74a5605dd81907cf2e6412a2f4202451d4a1f
Bug 474369 - remove nsVoidArray includes; r=ehsan

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extra : rebase_source : dd3abeb623fd8b784fd6ba639c88def84a4daf58