add cancel instance support and uninstall test
Merge remote-tracking branch 'origin/master'

Conflicts:
	softlayer_plugin/tests/test_plugin.py
Merge branch 'master' of https://github.com/cloudify-cosmo/cloudify-softlayer-plugin
Merge remote-tracking branch 'origin/master'

Conflicts:
	softlayer_plugin/tests/test_plugin.py
CFY-1661