Implement addon/window API.
Simplify hidden-frame implementation by using
addon/window instead of platform specific hidden one.
Write tests for system runtime.
Write tests for system/events.
Handle case where access of `runtime.XPCOMABI` throws.
Bug 841536 - Improve console message on some platform exception with undefined message/name
Bug 840014: tabs.open() and windows.open() now take a isPrivate option
Bug 819454: Avoid nuking module sandboxes when the application is shutting down.
Merge pull request #809 from Mossop/bug819454

Bug 819454: Avoid nuking module sandboxes when the application is shutting down. r=ochemeau
Address review comments.
Merge pull request #711 from Gozala/bug/system-event-tests@825215

fix Bug 825215 - Write tests for system/events. r=@ochameau
Addressing minor code styling issues.
Merge pull request #710 from Gozala/bug/runtime-tests@825216

Fix Bug 825216 - Write tests for system runtime. r=@ZER0
Hotfix Bug 825215 - Wait after GC-ing since debug builds don't collect that quick. a=@gozala
Merge pull request #790 from ochameau/exception-message

Bug 841536 - Improve console message on some platform exception with undefined message/name r=@erikvold
Bug 841536 - Improve console message on some platform exception with undefined message/name - address review r=@erikvold
Merge pull request #810 from ochameau/exception-message

Bug 841536 - Improve console message on some platform exception with undefined message/name - address review r=@erikvold
Merge branch 'master' into bug/addon-window@820953

Conflicts:
	lib/sdk/addon/runner.js
Merge pull request #698 from Gozala/bug/addon-window@820953

Bug 820953 - Expose DOM window to the add-on r=@Mossop
Revert "Merge pull request #698 from Gozala/bug/addon-window@820953"

This reverts commit 42cede06862471f3c05cb937cb3d2200b4d3218e, reversing
changes made to 0a7815dcad63db787ca542e648eeb29c2d8f5390.