add `Fat.KV_RO` which is a read-only subset of the filesystem.
Regenerate OASIS files with 0.4.0
bump to 0.9.0
Generate annot, bin_annot files and ensure principal typing
Travis: add cmdliner
Travis: further missing deps
Merge pull request #20 from avsm/add_kvro

Add V1.KV_RO interface