* docs/schemas/domain.rng: allow one <description> tag in the top level
of the <domain> to store user information as text
* src/conf/domain_conf.c src/conf/domain_conf.h: extend the structure
to store this text, grab it at parse time and save it back when
present after <uuid>
* src/capabilities.c, src/capabilities.h, src/domain_conf.c,
src/domain_conf.h, src/domain_event.c, src/domain_event.h,
src/interface_conf.c, src/interface_conf.h,
src/network_conf.c, src/network_conf.h, src/node_device_conf.c,
src/node_device_conf.h, src/secret_conf.c, src/secret_conf.h,
src/storage_conf.c, src/storage_conf.h, src/storage_encryption_conf.c,
src/storage_encryption_conf.h: Move to src/conf/
* src/Makefile.am: Add -Isrc/conf to the individual build targets
which need to use XML config APIs. Remove LIBXML_CFLAGS, LIBSSH2_CFLAGS
and SELINUX_CFLAGS from global INCLUDES and only have them in build
targets which actually need them. Create a libvirt_conf.la
convenience library for all config parsers
* src/hostusb.h: Remove bogus include of domain_conf.h
* tests/Makefile.am: Add -Isrc/conf. Remove bogus -I$builddir/src
since it never has any generated header files
* daemon/Makefile.am: Add -Isrc/conf
* proxy/Makefile.am: Add -Isrc/conf and cope with renamed files
* src/hash.c: Remove bogus include of libxml/threads.h
