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/plist.c

@@ -196,7 +196,8 @@ xbps_dictionary_from_metadata_plist(const char *pkgname,
 	xhp = xbps_handle_get();
 
 	plistf = xbps_xasprintf("%s/%s/metadata/%s/%s",
-	    xhp->rootdir, XBPS_META_PATH, pkgname, plist);
+	    prop_string_cstring_nocopy(xhp->rootdir),
+	    XBPS_META_PATH, pkgname, plist);
 	if (plistf == NULL)
 		return NULL;
 
@@ -209,7 +210,8 @@ xbps_dictionary_from_metadata_plist(const char *pkgname,
 		}
 		free(plistf);
 		plistf = xbps_xasprintf("%s/%s/metadata/%s/%s",
-		    xhp->rootdir, XBPS_META_PATH, pkgname, plist);
+		    prop_string_cstring_nocopy(xhp->rootdir),
+		    XBPS_META_PATH, pkgname, plist);
 		if (plistf == NULL)
 			return NULL;
 	}