Bug 944403 - disable Australis' add to toolbar/menu items when clicking empty bits of the tabstrip, r=mconley

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extra : rebase_source : ae2108d8e0f1fa8db60205dc19c2620d8c1d379b
Bug 941321 - try-finally all of Australis' begin/endBatchUpdate calls, r=mconley

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extra : rebase_source : 06102ada89853f201baacbca37dc9ced1243acca