Reduce the number of times we call rustc in our Makefile #2327
auto merge of #2586 : ebalint/servo/2327, r=jdm
gfx: Add display list optimization to eliminate clipped items before
submitting them to Skia.

40x improvement in painting time on Wikipedia.
auto merge of #2588 : pcwalton/servo/display-list-optimization, r=glennw

submitting them to Skia.

40x improvement in painting time on Wikipedia.

r? @glennw
gfx: Binary search for the start position when iterating over the slices
in a text run.

This makes painting of text display items faster and matches what Gecko
does.