Fix bug where P6 import module was not shipped

Fix IfcOpenShell#1382. You can now search property values agnostic of…

… pset names. Thanks stefkeB!

Minor fixes to slab/wall syncing and stability in changing thicknesses.

Improved date calculations during import and editing ensure that star…

…t / finish dates are always on working days.

New styles on sequencing gantt chart to show dependency arrows, criti…

…cal path, task groups, and milestones

Updating either a duration, start, or finish date for a task now auto…

…-updates the other attribute

Fix material unassignment greedy purging bug, and auto assign usages …

…of typed layer / profile sets.

Dumb slabs now are marked as parametric and inherit thickness from th…

…e slab type

Fix IfcOpenShell#1462. Standardise IfcOpenShell API to use Pythonic a…

…rgument names.

Really barebones UI to list space boundaries.