Squashed 'subtree/bokehjs/' changes from ddf1bec..35b33ba

35b33ba Merge branch 'legend_bug'
914e10f only round coordinates for rects, not for everything, and not for sub two-pixel distances
4cc464f fixed the legend bug, cleaned up master diff
c2fb0a7  goto http://localhost:5000/test/legend_test?filter=legend_test_overlap to see the legend bug
c91b837  merged
62d5a1b attempt to make lines sharper by rounding pixel coordinates
626bcd1  added memoize library
c4cd225  merged
201ed27  added memoization to ticking and text meauserment functions
bfa47d1 Merge branch 'subtree'
4eacc9e improve ticking on user bound axes when panning/zooming, etc
9e17cd3 Merge branch 'subtree'
770db70 fix axis rule placement errors due to insufficient precision
955dbe3 Merge branch 'subtree'
9ae86c7 revert last commit, re-ticking breaks with panning

git-subtree-dir: subtree/bokehjs
git-subtree-split: 35b33baea6aa094e6ebd8c309a1d3078522a0305
merge latest bokehjs
Merge branch 'master' of github.com:ContinuumIO/Bokeh