Pive

**Major changes**

* Modified the chart generation. No more CSS documents will be generated. CSS styles
are included within the javascript template directly.
* Users can now omit a destination div container (div_hook) to tell pive where to put
the visualization.
* New environment function allows users to only obtain the plain javascript code and its data.

**Minor changes**

* Refactoring
* Cleanup
* Added sample data
* Added sample charts

**Major changes**
* Fixed an issue while creating the chords in chordchart.

**Minor changes**
* Added a 'pive powered' badge.
* Added initial sphinx documentation.

**Major changes**
* Fixed an issue where visualization types were not correctly read.

**Minor changes**
* Refactoring
* Cleanup

**Major changes**

* First working version of pive: No changes documented.