Test notification bar for #459
Note: double_tap() doesn't work.
Merge remote-tracking branch 'mozilla/master' into issue_459
Use script to open notification bar.
Modified manifest.
Upaded fail message, removed unused code.
Merge remote-tracking branch 'askeing/issue_459'

Conflicts:
	gaiatest/tests/manifest.ini
Merge remote-tracking branch 'mozilla/master' into issue_456
repaired small nits after code review