Bug 922835 - Make youngestFrame a getter instead of managing it manually; r=past
Bug 923735 - Tracer should attach why to frame exit packets; r=robcee
Bug 925073 - Create a pref to enable/disable pretty printing in the UI; r=vporof
Merge m-c to fx-team.
Backout 6de71ba24d50 (bug 922835) because it was the wrong version of the patch. r=me
Bug 922835 - Make youngestFrame a getter instead of managing it manually; r=past