When trying to switch to a container that does not exist, it now removes that ctnr from the session list
When creating a ctnr, it is added to the users session variables. When deleting it is removed, and if user is currently in that ctnr they are switched to their default.
Edited for consistency
Merge branch 'master' of https://github.com/OSU-Net/cyder into ctnr_logic

Conflicts:
	cyder/base/views.py
Fixed ctnr_delete_session being called before permissions checking
Fixed another merge conflict
Fixed ctnr's not being deleted from ctnr session list properly
Users can no longer enter 00:00:00:00:00:00 into the mac address field
tablefy (reluctantly) takes lists too
Fixed interfaces being created with 00:00:00:00:00:00 as a mac address in tests.
Permissions for keyvalues now default to the objects permissions
Migrate 00 macs as blank
Swap the relationship between Vrfs and Networks

Before this commit, the Network model had a one-to-many relationship
with the Vrf model. This commit swaps the direction of the relationship.
Add schema migrations
Fix migrations after Vrf-Network relationship flip
Fix some recently broken functions
Fix a test and another broken function
Ranges now include % used in the interface
Updated keyvalue permissions for deleting a kv
Ctnrs in session now update accordingly to name change