Add data layer atom method to delete existing SMS
Merge branch 'master' of https://github.com/rwood-moz/gaia-ui-tests into delete_sms
Merge branch 'master' of https://github.com/mozilla/gaia-ui-tests
Delete existing SMS messages in test setup
Merge branch 'master' of https://github.com/rwood-moz/gaia-ui-tests into delete_sms
Workaround for bug 837029
Merge branch 'master' of https://github.com/rwood-moz/gaia-ui-tests into delete_sms
Merge branch 'master' into delete_sms

Conflicts:
	gaiatest/atoms/gaia_data_layer.js
Merge pull request #361 from bobsilverberg/delete_sms

This resolves the merge conflicts that are present in pull request #300