Adapt to V1 mirage-types cleanup in mirage/mirage@78ee76e8667e84fedc64bf2f781b0d7196cb2691
Merge branch 'split-libs' of github.com:avsm/mirage-tcpip into split-libs

Conflicts:
	lib/tcpip_stack_direct.ml
fix ocamldoc for channel
Merge pull request #45 from avsm/split-libs

Adapt for latest V1 types