util: Rename NetKAT_Util to Util, make it internal

The util module should not be an exported module.
util: remove functions that exist in Core, add banner
Merge pull request #294 from frenetic-lang/util

Don't export Util module, and clean it up
ctleanup: Open module to make lines more readable
ctleanup: Rework payload juggling
ctleanup: Remove redundant payload_bytes

Already defined in ocaml-openflow.
ctleanup: add type annotations to top-level definitions
topo: add stubs for functions in new topology API
Merge pull request #296 from frenetic-lang/topo

add stubs for functions in new topology API
Merge pull request #295 from frenetic-lang/ctleanup

Minor Controller refactorings
setset: Remove final traces of PacketSetSet
Merge pull request #297 from frenetic-lang/setset

Remove final traces of PacketSetSet
Initial Consistent Updates commit

Basic 2-Phase Commit algorithm, disabled

Basic consistent updates test app. Currently breaks when Controller actions get spliced in, which causes unrealizable mods. Easy fix is to stamp VLAN
Added barriers/ivars protocol

Updates working modulo topo discovery

Current topology discovery is super slow so we think every port is an external port
Added single-switch consistent update

More efficient per-switch consistent update
Block on barrier send before reading Ivar

Updates are working for tree,2,2!
Added consistent update flag. Reformatted.