Version 0.4.1

Update runtime dependency of json_api_client to be >= 1.1 so it works with flex-ruby-gem release v0.6.55 along with other gem dependencies which have a higher version of json_api_client.

Added better error reporting for users of the API.

This release is the old shift-base gem refactored to use the Shift::Api::Core namespace - the functionality hasn't changed at all from shift-base.

If switching from shift-base, please replace "Shift::Base" with "Shift::Api::Core" and change any requires to 'shift/api/core'