Test delete a contact for #493
Removed remove_confirm.py, move RemoveConfirm class into contact_form.py.
Merge remote-tracking branch 'mozilla/master' into issue_493

Conflicts:
	gaiatest/tests/contacts/manifest.ini
Merge remote-tracking branch 'mozilla/master' into issue_493
Modified locators from xpath to css selector.
Merged `RemoveConfirm` into `EditContact` class.
Merge pull request #504 from askeing/issue_493

Test delete a contact for #493