Allow learner groups to be created empty

When a new top level learner group is added a dialog will ask the user
if the group should be empty of full.
Merge pull request #713 from jrjohnson/611-fillnewgroups

Allow learner groups to be created empty
changed 'scheduled' icon color to #CDEE6A aka RGB 205:238:106
changed 'scheduled' AND 'is-published-tbd' icon color to #CDEE6A aka RGB 205:238:106
changing icon color to a better-contrasting blue-ish #2A60BA
Merge pull request #714 from thecoolestguy/701_scheduled_session_color_change

'scheduled' session icon color change