Big rollup

This is a fairly large rollup, but I've tested everything locally, and none of
it should be platform-specific.

r=alexcrichton (bdfdbdd)
r=brson (d803c18)
r=alexcrichton (a5041d0)
r=bstrie (317412a)
r=alexcrichton (135c85e)
r=thestinger (8805baa)
r=pcwalton (0661178)
r=cmr (9397fe0)
r=cmr (caa4135)
r=cmr (6a21d93)
r=cmr (4dc3379)
r=cmr (0aa5154)
r=cmr (18be261)
r=thestinger (f10be03)