NetKAT end-to-end
Added Choice policy constructor
merge
Added Choice policy constructor
(cherry picked from commit d1936042a9d15e3d875f74a84954c660bd6d0dba)
Added Choice to dehopification
Fixed (a) sequential composition bug
Merge pull request #121 from jnfoster/master

Bug fixes
Added dataflowesque optimizations, much more scalable. Also reduced number of tags generated
merge
No longer build frenetic and maclearning executables.

Reviewed by Spiros.
snapshot commit
Clean up/refactor optimizations to use lattice of values
merge from reitblatt fork
debugging snapshot to switch to Spiros'
dehop: fix bug in dataflow lattice merge function

If one of the tables is empty, merge default across values of the other
table before returning.
Added safe version of global optimzations to be called during distribution. Can now compile policies w/ 4 seqs and 4 topo terms
Added comments to optimization in dehop, specifically use/don't use instructions
apparently the 'safe' optimizations aren't so safe to call in arbitrary contexts. Commenting off to debug later
Merge pull request #123 from frenetic-lang/dehop

Kinder, simpler dehopification + faster optimization pass Edit
Fixed to pretty-printer

Fixed to gel with Nate's update to parser