fixed Groups::GroupsController#fetch_member_group to work with empty group name
only run all of the handle validations, if it isn't the empty string
Groups::GroupsController: repaired before_filter :fetch_group
This fixes destroying groups and networks
(possibly) clarified wording for network_initial_member
Groups::GroupsController: removed handling of initial member group for networks from controller. Only checking permission now.
Network: added initial_member_group handling
use Network#initial_member_group instead of 'member_group_name' param in group (network) creation form
networks now require an initial group, to be created. existing networks aren't affected though.
added initial_member_group option to NetworkTest#test_creation
validates_handle: simplified check for empty value
improved NetworkTest#test_creation, added test to check that network creation without initial_member_group is not allowed
Merge pull request #76 from Crabgrass/bugfix/4314-initial-group-for-network-is-required

initial group for network is required