IPython 4 and Python 3 compatibility

This release adds:

• IPython 4.0 compatibility
• Python 3 compatibility

Additionally, it drops:

• IPython 2.x compatibility

Fixed typo in README.

v0.1.6

Bumped to version 0.1.6.

Weighted heatmaps and datasets

• Added possibility of including weights in heatmap data.
• Added a datasets module to allow new users to play around with data
  without having to find their own dataset.

Bugfix release

• Fixed a bug that arose when using the heatmap with IPython2.3 in the
  previous release. The bug was caused by the slightly different traitlets API
  between the two IPython versions.

Minor heatmap improvements

• Exposed the 'maxIntensity' and 'radius' options for heatmaps.

Bugfix release

Version 0.1.1

Bugfix release.

• Ensures the notebook extensions are actually included in the source
  distribution.

Initial release.

Version 0.1

Initial release.

• Allows plotting heatmaps from a list / array of pairs of longitude, latitude
  floats on top of a Google Map.