Add ocaml-leveldb 1.0.0.
Add obigstore 0.9.0.
Add virtual package conf-leveldb.1, make ocaml-leveldb.1.0.0 depend on it.
Replace obigstore.0.9.0 with obigstore.0.9.1.
Replace ocaml-leveldb.1.0.0 with ocaml-leveldb.1.0.1.
Rename ocaml-leveldb package to leveldb.
Replace leveldb.1.0.1 with leveldb.1.0.2.
Fix Travis

Closes #1551
Merge branch 'master' of git://github.com/mfp/opam-repository into mfp-master
Travis: fix the installability detection.
leveldb: add missing omake dep and libsnappy deps
Merge branch 'master' into mfp-master
leveldb.1.0.2: link explicitly against libstdc++ (and -lm for good measure).
leveldb.1.0.2: also link against libsnappy.
obigstore.0.9.1: disable parallel build so as to get more clear CI logs.
obigstore.0.9.1: depends on cryptokit.
Revert "obigstore.0.9.1: disable parallel build so as to get more clear CI logs."

This reverts commit ec3f229fab90b5ae794ca1663a67e233712718ee.
Merge pull request #1541 from mfp/master

New OPAM packages: ocaml-leveldb.1.0.0 and obigstore.0.9.0