Move 'chain' handling to sub-module Entry.Chain

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Pull out the main 'filesystem' type, outside the Lwt monad

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Remove Lwt.t from the main signature definitions

Since our implementation and tests are all Lwt-based, we mix in
the Lwt.t type when we include the signature.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Resync BLOCK_DEVICE signature with mirage-types V1

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Remove Lwt_unix implementation, depend on mirage-block-unix

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Rename ocamlfind package fat-format to fat-filesystem

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Release 0.5.0

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #6 from djs55/tidy-up

Resync BLOCK_DEVICE with mirage-types V1