Vcoclient

Added:
- added edges_get_agg_lm to get aggregated link statistics
- added stats option to almost every method. Didn't documented it yet but a very cool feature!

Changed:
- architecture change on how arguments are getting generated
- now login and logout are new methods in the class

Added:
- gateway_get_edges is a new method which gets the edges behind a given gateway
- enterprise_get_gateway is a new method which gets the gateways behind edges

Changed:
- edges_get method parameter ``id`` changed to ``enterpriseid`` to make sure we are consistent
- get_edges_lm method will convert user time to epoch to be more consistant
- Updated README to reflect new methods and changes

Changed:
- Fixing bug in setup.py

Added:
- new method for ``edge_get_lm`` which gets the link_metric of a given edge for a given enterprise.
- Added more description to given methods in argparse.
- Added envionment variables for verifying SSL (VCO_VERIFY_SSL) and cookie path (VCO_COOKIE_PATH)
Changed:
- Fixing API payload extraction
- Fixing error handling when method is not defined
- Making setup.py more reliable e.g. installing not from directory itself

Changed:
- Fixing bug in logout
- Added travis testing for overall package

Changed:
- Fixing bug in setup.py
- Printing out help if no method used in vcoclient.py