No need for custom mac_linux as it's the same as netaddr.mac_eui48
removing the deepcopy monky patch for netaddr.

Issue mentioned drkjam/netaddr#21 is fixed upstream and is available
from version 0.7.8 of netaddr. (fixed a year ago)
Fixed #3 : search in admin will work now
Better look up preparation. Allow only sensible lookups.

Django admin uses icontains. But it make sense to allow variants of
exact and contains. Which allow Q(mac__eq=value) and
Q(mac__contains=value) etc.,
Even though with current implementation of storing mac as integer in DB,
contains doesn't yield any result with partial mac data.
catch AddrFormatError on admin search
Merge branch 'kra3-master'
 Better to return None, rather than raise an exception

 To get django-admin working properly.
completely merging in github.com:kra3/django-macaddress-ng
 Create .travis.yml (@TODO: fix dependency setup and test execution)