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
xen: generate a main.xl during configure

Note we don't configure block or network devices. To compensate we
add some examples and documentation links to the config file.
Merge pull request #154 from djs55/add-xen

xen: generate a main.xl during configure
Update CHANGES
Merge pull request #155 from djs55/add-xen

Update CHANGES
The HTTP dependency now also installs `mirage-tcp-*`.

Otherwise we get a dependency failure as cohttp doesnt compile
the Mirage backends.
bump to 1.0.3 working version
Merge pull request #158 from avsm/master

Fix HTTP/cohttp dependencies in autoinstall
Always call ocamlbuild on every `make` by declaring the main target PHONY.

Closes mirage/mirage#150
Merge pull request #159 from avsm/master

Always call ocamlbuild on every `make` by declaring the main target PHON...