added PUT method to fact handler
added test
separated handlers
added delete method

Conflicts:
	nailgun/nailgun/test/test_cluster_changes_handler.py
fixed pep8 problems added tests
full test for custom attributes handler and deployer

Conflicts:
	nailgun/nailgun/test/test_cluster_changes_handler.py
doc for 404 added
test for orchestrator handler and deployer are separated
direct deployment surpasses validation
some flake8 changes
deployment check specified
last fixes for new deployment exception handling
debug to warning log
Merge pull request #1491 from Mirantis/PRD-1582-2

custom attributes disabled validation