Remove python3 incompatible exception syntax.

Change-Id: I5f0687a83362ceebf03bae4a0a5b109aad7e5200
Move tests into project package.

There are several reasons for this. One is that the majority of
OpenStack packages behave this way. The second is that it makes writing
software that extends something easier to test (which is a clear usecase
for openstackclient) And third, tests/__init__.py implies a global
package named "tests" - which I'm pretty sure we're not providing.

Change-Id: Ic708ffd92aea78c2ffc1a8579af0587af4fca4ff
Add methods for user and group interactions

* Add user to group
* Contains user in group
* Remove user from group

Change-Id: If5219fa9d4761d7b97950c39556b3e1b8aab6517
Merge "Remove python3 incompatible exception syntax."
Merge "Move tests into project package."
Finish up v3 role commands

* Add remove role
* Add --role to group list
* Add --role to user list
* Fix groups in AddRole()
* Remove the tweaks to utils.find_resource for domains; will address
  that across domains, projects, users and groups in another patch.
  I want to nail down the structure of these commands and get that into place

Change-Id: I8673dd8221ef88978dada5a2833c187026bdb31a
Merge "Add methods for user and group interactions"
Merge "Finish up v3 role commands"