When updating manifest from a non-checkout put changes into local_changes section.

Instead of overwriting manifest entries when updating against a local copy (not clone) of
the tests, put differences into the local_changes section, rather than overwriting the
data about upstream. This makes resyncing changes with upstream easier.
fixup! When updating manifest from a non-checkout put changes into local_changes section.
media-src csp positive and negative tests
Removal of .ds_store
Simplify the test for cross-origin progress events.
Move the test for cross-origin progress events into place.
Merge pull request #1460 from Ms2ger/progress

Cleanup the test for cross-origin progress events; r=annevk
Add some basic manual tests and an idlharness test for Gamepad API.
Merge pull request #1458 from luser/gamepad-tests

Add some basic manual tests for Gamepad API; r=Ms2ger
Sync unitless length quirk with https://github.com/whatwg/quirks/commit/78352c6253798f0bd9316680637fc833f7c08919
Tweak how quirks tests are set up to work better in gecko
Make quirks reftests actually link to the reference
Merge pull request #1468 from zcorpan/quirks-onload-tweak

Tweak how quirks tests are set up to work better in gecko
Merge pull request #1469 from zcorpan/quirks-reftest

Make quirks reftests actually link to the reference
Merge pull request #1467 from zcorpan/unitless-length-whitelist

Sync unitless length quirk with ...
whitespace, hostname generation fixups
Add assert description to make judgement easily

- It is difficult for user to judge test result if there is nothing on the page.
Put the test criteria before the test content
Merge pull request #1470 from JianfengXu/audio/update

Add assert description to make judgement easily
Merge pull request #1446 from w3c/jgraham/manifest_local_changes

When updating manifest from a non-checkout put changes into local_changes section