Stray code from NetCore

These files are for executables that were no longer built by
oasis. That's why I missed them in my earlier cleanup.
dropped NetCore from Stream/Util. Killed ghost file NetKAT_Pretty
Merge pull request #134 from frenetic-lang/netcore-dead-bits

Stray code from NetCore
Merge branch 'master' into automaton

Conflicts:
	lib/netcore.mllib
	setup.ml