CLOUDIFY-2431 plugins context initial commit
CLOUDIFY-2431 changed decorator to method invocation because of celery imports problem
CLOUDIFY-2431 raise exception if ambiguity in capabilities
CLOUDIFY-2431 added a cloudify context identifier constant for clarity
Merge pull request #8 from CloudifySource/feature/CLOUDIFY-2431-plugins-context

CLOUDIFY-2431-plugins-context
CLOUDIFY-2433 added related node api
CLOUDIFY-2433 flake8
Merge pull request #9 from CloudifySource/feature/CLOUDIFY-2431-plugins-context

CLOUDIFY-2433 added related node api
Merge branch 'develop' into feature/CLOUDIFY-2370-plugins-as-python-libs

Conflicts:
	cloudify/tests/test_deployment_node.py