Squashed 'subtree/bokehjs/' changes from 5a07173..7ba0e1e

7ba0e1e simple boxplot
4d6cbc6 partial work for boxplots

git-subtree-dir: subtree/bokehjs
git-subtree-split: 7ba0e1e57bd6a0664acb1a8d1e99b3324ae560aa
Merge commit 'cd4506f6d601eec9a14f2b5ee2c41474802a06c2'