on delete backend, disable monitoring of machines
add spinner when deleting provider
Merge branch 'master' into disable_monit_on_bd_removal

Conflicts:
	src/mist/io/static/main.css
change warning text on backend removal
Merge branch 'disable_monit_on_bd_removal' of https://github.com/mistio/mist.io into disable_monit_on_bd_removal