Python-pptx

++++++++++++++++++

- Add `GroupShape`, providing properties specific to a group shape, including
its `shapes` property.
- Add `GroupShapes`, providing access to shapes contained in a group shape.
- Add `SlideShapes.add_group_shape()`, allowing a group shape to be added to
a slide.
- Add `GroupShapes.add_group_shape()`, allowing a group shape to be added to
a group shape, enabling recursive, multi-level groups.
- Add support for adding jump-to-named-slide behavior to shape and run
hyperlinks.

++++++++++++++++++

- Add `SlideShapes.build_freeform()`, allowing freeform shapes (such as maps)
to be specified and added to a slide.
- Add support for patterned fills.
- Add `LineFormat.dash_style` to allow interrogation and setting of dashed
line styles.

++++++++++++++++++

- Add `SlideShapes.add_movie()`, allowing video media to be added to a slide.

- fix 190 Accommodate non-conforming part names having '00' index segment.
- fix 273 Accommodate non-conforming part names having no index segment.
- fix 277 ASCII/Unicode error on non-ASCII multi-level category names
- fix 279 BaseShape.id warning appearing on placeholder access.

++++++++++++++++++

- 267 compensate for non-conforming PowerPoint behavior on c:overlay element

- compensate for non-conforming (to spec) PowerPoint behavior related to
c:dLbl/c:tx that results in "can't save" error when explicit data labels
are added to bubbles on a bubble chart.

++++++++++++++++++

- add Chart.chart_title and ChartTitle object
- 263 Use Number type to test for numeric category

++++++++++++++++++

- add DataLabel.font
- add Axis.axis_title