Convert a bunch more marionette.tap(el) into el.tap()

Conflicts:

	gaiatest/tests/everythingme/test_everythingme.py
	gaiatest/tests/ftu/test_ftu_skip_tour.py
Xfail video tests due to 'load videos' overlay not clearing after pushing resources to SDCard
Tap delete button on Gallery image causes a socket.timeout
Merge pull request #896 from zacc/xfail_test_gal_del_img_timeout

Tap delete button on Gallery image causes a socket.timeout
Merge pull request #895 from zacc/xfail_vid_tests

Xfail video tests due to 'load videos' overlay not clearing after pushin...