This patch adds a new element <title> to the domain XML. This attribute
can hold a short title defined by the user to ease the identification of
domains. The title may not contain newlines and should be reasonably short.
*docs/formatdomain.html.in
*docs/schemas/domaincommon.rng
- add schema grammar for the new element and documentation
*src/conf/domain_conf.c
*src/conf/domain_conf.h
- add field to hold the new attribute
- add code to parse and create XML with the new attribute
