Re-add support for multiple categories per option
Re-add support for multiple categories per option

This allows options to appear in more than one table by adding a
space-separated list of categories in the flagmappings file. This
was supported before, but I broke it in my rewrite.

Change-Id: Iecfa32653cc619e0a1230c307ce08325a3edddc7

savinash47/openstack-doc-tools,openstack/openstack-doc-tools,savinash47/openstack-doc-tools,openstack/openstack-doc-tools,savinash47/openstack-doc-tools