Allow for users to be in groups [MJ-294]
Add group membership method used in the user_passes_test decorator as well as some simple tests [MJ-294]
Improve group test, add docs [MJ-294]
Add example usage to docstring [MJ-294]
Add inputs/output to docs, remove errant save() [MJ-294]
Merge branch 'master' into accounts-user-group-support__MJ-294
Remove the addition of default groups [MJ-294]
Merge pull request #192 from DirectEmployers/accounts-user-group-support__MJ-294

Accounts - add ability for users to be members of groups [MJ-294]