Output custom logging during automated tests.
Allow switching between parseable and normal test output.
Merge branch 'master' into bug816688

Conflicts:
	lib/sdk/test/harness.js
Only apply the implicit PageContext if there are no declarative contexts and no context listeners in the worker.
Merge pull request #706 from Mossop/bug826080

Bug 826080 - New context-menu module applies the PageContext in cases where it shouldn't. r=@gozala
Show stacks in the event of unexpected failures.
Merge pull request #669 from Mossop/bug816688

Bug 816688 - Output test messages in the tinderbox standard. r=@gozala
Back out Merge pull request #630 from ZER0/window.tabs/bug804935 for causing debug failures.

This reverts commit f2c93bd8cac8c48ff11f6ae2f4ce84d99e037ded, reversing
changes made to b205f229a706aa8d8c622d4a3cacda5e0705e5ed.