Use d3 to display mem utilization.

Get mem utilization data, and modify it for stacked layout
Draw stacked graph
Adjust width and margin
change number of data points to 300
Update user model to include additional fields. #401
Add model for group. #401
Improve create user backend api. #401
Snapshot rollback issue

Don't allow user to submit snapshot rollback request
when there are no writable snapshots
Snapshot rollback issue

Don't allow user to submit snapshot rollback request
when there are no writable snapshots
Add tests for user api. mostly stubs. #401
Snapshot rollback issue # 511

Don't allow user to submit snapshot rollback request
when there are no writable snapshots
Snapshot rollback issue # 511

Don't allow user to submit snapshot rollback request
when there are no writable snapshots
Add all necessary post tests for user api. #401
Improve user create api. #401
Improve/refactor user delete and edit api. #401
Remove trailing / from user api. #401
Add helper method to validate public keys. #401
Improve/refactor low level useradd and userdel logic. #401
Add tests for pw and pub key change/put api. #401
Update setup view for new user model updates. #401