Add support for fetching associations
Get rid of json extension in vcr cassettes
Add rates support
Remove yard from Guardfile

Sometimes it doesn't work and it makes specs take more time
Fix for running specs via guard
Better specs for checking API response

* Added missing valid responses
* Fixed BOOKINGSYNC_URL in some specs
Fix @return syntax in docs
Fix passing resource object to edit methods
Merge pull request #39 from BookingSync/associations-support

Associations support