Merge pull request #115 from sk2/master

merge back to interfaces
update doc, work on json tree for nidb
copy interface ids back from nidb to anm overlays, condense to brief for brevity
fix issue with interface descriptions for secondary loopbacks
work on mpls, vrfs, mpls ldp
work on vrfs, mpls ldp
remove testing code
allow access to interface from nidb
smaller interface labels
add todo
copy description as well as type from anm
add to mpls ldp if bound in that overlay
remove debugging
more work on vrfs
more work on bgp vrfs
work on vrfs and bgp sessions, tidied up bgp sessions
ibgp vrf
continued vrfs
sort returned json keys
add docstrings