Split out from calligra.

- Conflict with calligra < 3.1.0, some icons were part of the main
calligra package previously
- Add 0001-Plan-fix-build-with-Qt-5.6.patch to fix build on Leap 42
- Initial package of version 3.1.0, plan is released separately
from calligra now
- Changes since 3.0.1 (where it was still part of calligra):
* Add dialog to be able to edit multiple tasks at once
(kde#310937)
* Provide expand all/collapse all in context menu (kde#313606)
Expands/collapses selected item(s) and all children
Retains the treeviews expanded rows across operations
* Printing: Make changes to page layout persistent (kde#385084)
* Open Document Text format report generator added
Adds the abillity to generate reports in odt format directly.
Reports can be viewed using an odt viewer like Calligra Words
or LibreOffice Writer
Report templates are also in odt format and can be designed
using e.g Words or Writer
* Add support for sharing resources in multiple projects
* Improved context help and documentation
* Add support for automatic holidays generation
* Calendar view: Handle context menus with no calendar
* Replace the file centric startup page with page more suitable
for projects
* Add editing and reloading of task modules.
* Gantt view: Fix possible crash when deleting gantt view with
large projects
* Gantt view: Fix issue with task dependencies not cleared in
certain situations
* Fix undo/redo issue with modifying project target times
* Fix potential crash in Cost Breakdown View
* Fix potential crash when creating new project from current
project
* Fix performance issue in chart view
Note:
* Support for scripting is discontinued
* Reports using KReport is not supported in this release