Fix the HTTP stack

- The IP drivers now always takes a callback as argument (lib_test/ip needs to be fixed)
- The HTTP drivers do the same thing and always take a callback as argument
Fix the IP tests after the API change in mirage
Add an HTTP test
Fix KV_RO packages for OPAM auto-install
bump to 1.0.2
ignore img files in lib_test
Merge pull request #135 from avsm/samoht-master

Release 1.0.2: HTTP support and OPAM installation fixes
Travis: fix dependencies
Travis: reduce verbosity
Bump version to 1.0.2
Merge pull request #136 from avsm/master

Travis: fix dependencies
Be less agressive on 'mirage clean'

Do not remove the OPAM packages (and do not remove the 'mirage' package in the same occasion).

Fix #143
Update CHANGES
Merge pull request #144 from samoht/master

Do not remove the `mirage` package when doing `mirage clean`
Travis: update deps (missing crunch)
Travis: correctly cd to the test dir
travis: remove 3.12.1 from testing
Merge pull request #145 from avsm/master

Travis: update deps (missing crunch)
Http: simplify example by using `Cstruct.copyv` instead of manual concat
Merge pull request #148 from avsm/master

Http: simplify example by using `Cstruct.copyv` instead of manual concat