Re-add xl config file parser (previously lost in xen-api history)

Signed-off-by: David Scott <dave.scott@citrix.com>
Fix missing character in .mly, delete autogenerated .ml

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #3 from djs55/add-parser

Re-add xl config file parser (previously lost in xen-api history)