add cmds descriptions
pre && post action declaration
change input format
change input format, add environments variables
first checks implementation
In [1]: from pumphouse import checks

In [2]: p = checks.PumpHouseShellCheck({"input": ["127.0.0.1", "127.0.0.2", "10.0.0.3", "10.0.0.4" ], "env": {"COUNT": 1}, "cmd": "ping -c\${COUNT} ^" });

In [3]: print p.run()
['10.0.0.4', '10.0.0.3']
review fixes
fix typo
simplify shell commands
don't run if null input
Add exception when check failed
Merge remote-tracking branch 'origin/taskflow-checks'

Conflicts:
	doc/samples/api-config.yaml
Import task module and fix base classes
Fix server removal trigger in cleanup
Remove print statements
Merge master into floating-ip-migration-tasks
Adds server events generation for users and images migration
Adds event generation for flavor creation
Fixes pep8 for user.py
Fixes some of pyflake issues for user.py tasks