New configuration scheme changes, round 1.

- Configuration file 'xbps-conf.plist' has been splitted off into
  two files: conf.plist and repositories.plist. By default they
  are stored in etc/xbps.
- Changed some members in xbps_handle struct, mostly to make it easy
  to change its value in {cache,root}dir and conffile.
- Made xbps_init() release proplib objects as soon as we don't need
  them, that way it uses 35% less of memory or in some cases even more.

There will be another commit that will implement to read new virtualpkg
settings by the user, as specified in:

	http://code.google.com/p/xbps/issues/detail?id=12

lib/regpkgdb_dictionary.c

@@ -66,7 +66,8 @@ xbps_regpkgdb_dictionary_init(struct xbps_handle *xhp)
 	if (regpkgdb_initialized)
 		return 0;
 
-	plist = xbps_xasprintf("%s/%s/%s", xhp->rootdir,
+	plist = xbps_xasprintf("%s/%s/%s",
+	    prop_string_cstring_nocopy(xhp->rootdir),
 	    XBPS_META_PATH, XBPS_REGPKGDB);
 	if (plist == NULL)
 		return ENOMEM;