Users can no longer enter 00:00:00:00:00:00 into the mac address field
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
Updated keyvalue permissions for deleting a kv
Range.get_allowed_clients() should return a list
Iterate through iterable things
Merge pull request #14 from murrown/church29-MAC_Validation

Migrate 00 mac addresses as blank
Merge pull request #267 from church29/MAC_Validation

Users can no longer enter 00:00:00:00:00:00 into the mac address field
Merge pull request #272 from church29/KeyValue_Permissions

Permissions for keyvalues now default to their respective object's permissions
Merge pull request #277 from drkitty/flip_vrf-network_relationship

Flip Vrf–Network relationship. Fully Functional, all tests pass.