Bug 824454; use the resolution scale in OMTA transforms. r=cjones; a=blocking-basecamp

--HG--
extra : rebase_source : 8f045dd319418b771c5f31ca2f3477ab5673a5ad
Bug 819061 - [Apps] Remove workaround from Bug 813468 once Bug 815523 is done r=ferjm
Bug 827750 - Inhibiting HTTP cache for app updates. r=fabrice