travis.sh: don't set OPAMVERBOSE

Travis truncates output to 10,000 lines, which is exceeded currently.
Thus, if there’s an error after that, we cannot see what the problem
was.
create dev version of opam package

This can serve as the master version of Biocaml’s opam package
description. Developers can add it as an opam repo, and we can copy
from here when doing a release to the main opam repository.
OMakeroot: use PROJECT variable in install

It so happens PROJECT is the same as LIB_NAME, but semantically PROJECT
is the correct variable to name the ocamlfind package on.
opam: remove build-test

Firstly, we weren’t installing the tests, so pointless to compile them.
Installing won’t help unless we also install all the data files the
tests depend on. Not worth it right now as tests are only run by
developers.
opam: generate biocaml.install file

Still need to run `omake install`. This only handles additional files
not handled by ocamlfind.
opam: require OCaml version >= 4.01.0

Due to module type constraint changes as reported
[here](https://sympa.inria.fr/sympa/arc/caml-list/2014-01/msg00237.html)
 and in [PR#6090](http://caml.inria.fr/mantis/view.php?id=6090).