Bug 890135 - Switch B2G's "gc log" dumping to produce all-traces logs by default. r=mccr8

This patch also adds "abbreviated gc log", which produces a not-all-traces CC log.
Bug 888511 - Fix leak of DOMRequests in Webapps::Launch code. r=fabrice
Bug 888511 - Follow-up: Fire onsuccess properly in Webapp.js after launching an app. r=fabrice
Bug 889984 - Don't leak objects which "inherit" from DOMRequestIpcHelper the associated window is closed. r=fabrice