Add command to map uaa groups to external group

[#74344702] https://www.pivotaltracker.com/story/show/74344702

Signed-off-by: Filip Hanik <fhanik@gopivotal.com>
Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Bump version to 3.1.0

Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Fetch cf-uaa-lib gem from github

Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Add command to list all group mappings

TODO: Pagination
[#74344702]

Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Add command to unmap uaa scopes from external groups

[#74344702]

Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Add pagination for listing group mappings

Signed-off-by: Rob Gallagher <rgallagher@pivotallabs.com>
Fix typo in group mappings help

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Validate group_id and external group in group unmap command

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Require that the group id and external group are provided

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Use group name instead of id for unmap command

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Require external group on map command

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Don't group group mappings by display name

[#74344702] https://www.pivotaltracker.com/story/show/74344702
Remove dependency of cf-uaa-lib on github source code
Paginate uaac users by default