2014-01-22: merge stable into default

merge stable into default

diff --git a/.hgtags b/.hgtags
--- a/.hgtags
+++ b/.hgtags
@@ -10,3 +10,4 @@ df64e82e0920bdd079d77cd4829bac9d30461a25
 f9c6e637d91d107bbf2ad807f30dc04150ddb251 v0.5.4
 3f72f85e4cddf57e5e6c84c735f554f330d3b88b v0.5.5
 2ae2c7c154e0c80acd21bdb2dace1c98a0a8d7a7 v0.5.6
+fb1b0fb41bc768485f582f3f5af16478aa6212a1 v0.5.7