fix(interface): replace empty interface with InterfaceGenerator
Initial tests for PhysicalInterface, BondInterface, and VLANInterface
fix(vlan): Update VLAN parsing to support alternate naming schema

Moved the VLAN ID parsing into the stanza processing. Added support
for vlan[0-9]* parsing.
refactor(raw,slaves): Move parsing for raw devices and bond slaves
fix(bond): Fix bug in bond heirarchy generation

Setting bond1 to enslave bond0 resulted in a generated config where
bond1 enslaves itself. No good.
test(interface): Add tests for interface parsing
fix(errors): Export error types and make parsing more robust
tests(stanza): Add tests for stanza parsing

This adds a number of tests for the stanza functions. These tests
should be exhaustive.
test(network): Add tests for top-level network functions

This adds exhaustive tests for the functions in network.go.