Trivial fix for Async 111.13.00
Merge pull request #124 from frenetic-lang/async_111.13.00_fix

Trivial fix for Async 111.13.00
lattice: move pattern to submodule, define lattice ops
lattice: use new ocaml-packet.quickcheck API
lattice: add arbitrary instance for Pattern.t
lattice: quickcheck tests for Pattern.t lattice operations
lattice: add Pattern.disjoint
lattice: add Pattern.eq for semantic equality

Currently it's the same as structural equality. Hopefully this will be
preserved.
Merge pull request #126 from frenetic-lang/lattice

Implement lattice operations for patterns
v0.4.0 release
fix indent issue
fix complexion for oxm module
add to_string for MultipartReply and PacketIn
indent fix

PacketIn:
 - fixe padding after the Match field
 - fixe the field of the payload

add rountrip test for:
 - PacketIn
 - MultipartReply
add back the length field for tableFeature
standardise the marshal of ofp_desc
add an arbitrary_strings of arbitrary len fill with 0
Capabilities: add to_string
SwitchFeatures: add to_string and sizeof
merge of PortReason and PortStatus
add module QueueStats
 - to_string
 - rountrip test
add queueStats to multipartReply