show user review tips when low app rating is given (bug 874947)

https://bugzilla.mozilla.org/show_bug.cgi?id=874947
http://cl.ly/image/2G3735172Y3h/Screen%20Shot%202014-06-06%20at%2010.12.52%20AM.png
http://cl.ly/image/2p3j183d1d1o/Screen%20Shot%202014-06-06%20at%2010.14.29%20AM.png
http://cl.ly/image/3f10411k3s1Y/Screen%20Shot%202014-06-06%20at%2010.17.53%20AM.png