ENH: html tooltips for points

Closes #44, perhaps.
ENH: html tooltips for points

Closes #44, perhaps.
Merge pull request #52 from aflaxman/html_tooltips_

ENH: html tooltips for points
TST: remove test with color=None; fails in matplotlib 1.3
DOC: update features list and authors list
sync with upstream
BUG: make html tooltips work in ipython notebook
Merge pull request #56 from aflaxman/html_tooltip_in_notebook

BUG: make html tooltips work in ipython notebook
BUG: update __all__ in mpld3.plugins
specify IPython version required in enable_notebook
Merge branch 'upstream'