Ported: ipv4net and ipv6net

Signed-off-by: Alexander Kastius <alexander.kastius@student.hpi.uni-potsdam.de>
Merge branch 'racktables-html5' of https://github.com/acidix/racktables into racktables-html5
Started porting ipv4space and ipv6space.

Signed-off-by: Alexander Kastius <alexander.kastius@student.hpi.uni-potsdam.de>
Merge branch 'racktables-html5' of https://github.com/acidix/racktables into racktables-html5
Ported: ipv4space, ipv6space, tagtree

All ports done.

Signed-off-by: Alexander Kastius <alexander.kastius@student.hpi.uni-potsdam.de>
Merge branch 'racktables-html5' of https://github.com/acidix/racktables into racktables-html5