Update to mirage-types with V1.BLOCK and 'id' function

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
'make uninstall' should work irrespective of whether configure has run

In particular opam needs to run a plain 'make uninstall'. We make
this work by automatically running configure if it hasn't been
run manually yet.

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Release 0.7.0

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #18 from djs55/fix-block

Release 0.7.0