UD-215: rename add developer button.
Merge branch 'master' of github.com:codenvy/user-dashboard
UD-214: display message when there is no members in the workspace.
Merge branch 'master' of github.com:codenvy/user-dashboard
UD-216: make impossible to delete owner.
Merge branch 'master' of github.com:codenvy/user-dashboard into UD
Merge pull request #74 from codenvy/UD_A

Changes on issues UD-212, UD-214, UD-215, UD-216