Add fat-filesystem.0.6.0
Add mirage-block-unix
Correct a version constraint for fat-filesystem

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Add mirage-block-xen
Merge branch 'add-fat-filesystem' of git://github.com/djs55/opam-repository
mirage-block-unix: fix deps and constraints
fat-filesystem: fix constraints
fat-filesystem: add cmdliner, re deps
Merge pull request #1380 from mirage/master

fixes for #1378