Merge branch 'feature/object_or_href_or_string' into develop

* feature/object_or_href_or_string:
  Modifying Account.add_group() method.
  Adding tests for Account.add_group().

This commit adds flexibility to the Account.add_group() method.

It allows developers to specify the group as an object, href string, or group
name.  This makes it much easier for developers to work with, since they need to
do much less work upfront.
Cleaning up the classifiers stuff.

This makes our setup.py script a bit nicer, as it's a bit simpler.
Merge remote-tracking branch 'upstream/development' into develop

* upstream/development:
  always ensure data when working with custom data resource
Merge branch 'feature/object_or_href_or_string' into develop

* feature/object_or_href_or_string: (42 commits)
  Adding better illustrative examples.
  Fixing typo.
  Updating changelog.
  Adding better examples to the has_accounts and has_groups helpers.
  Updating _resolve_group and _resolve_account docs.
  Fixing implementation bugs.
  Adding tests for Group.has_account() and Group.has_accounts().
  Implementing Group.has_account().
  Implementing Group.has_accounts().
  Adding docstring for Group.has_account().
  Adding two skeleton methods.
  Renaming utility methods:
  Updating ValueError wording.
  Resolving unmatched name params for Group helper methods.
  Adding proper test URLs.
  Using client.BASE_URL.
  Using client.BASE_URL.
  Removing Group.unique_attrs.
  Refactoring the Account._resolve_group() and Group._resolve_account() helpers.
  Adding necessary import.
  ...
Merge remote-tracking branch 'upstream/development' into develop

* upstream/development:
Merge pull request #40 from rdegges/develop

Release 1.1.0