Revert "Bug 922558: Add contextMenu.PredicateContext. r=Mossop"

This reverts commit 8f80dfcf09621dc13ae6b4fc2214378fa7fe7ead.
Implement sequence lazy manipulation utils.
Merge pull request #1314 from Gozala/bug/sequence@854982

Bug 854982  - Implement lazy sequence manipulation library. r=@erikvold
Bug 946343 - Implements --manifest-overload r=@erikvold
Bug 945315 Testing that using the translators key for package.json actually works
Merge pull request #1318 from erikvold/945315

Bug 945315 Testing that using the translators key for package.json actually works r=@jsantell
Bug 947802 (part 2) - Replace enumerateReporters() with getReportsForThisProcess(). r=mccr8.
Remove docs and docs tests
Merge pull request #1322 from wbamberg/remove-docs

Bug 948606: Remove docs and docs tests. r=Mossop
Add few more sequencing functions.
Merge pull request #1324 from Gozala/bug/more-seq@787390

Bug 787390 - Add few more sequencing functions. r=@erikvold
Bug 922558: Add contextMenu.PredicateContext. r=Mossop