If a filename ends with '.iso' we assume the format is Raw

This allows us to handle the case of pre-created .iso images.

Fixes #7

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge branch 'master' of git://github.com/xapi-project/ffs
Update to 0.9.6

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