bim.reassign_class wasn't considering that root.reassign_class will also reassign class for occurrences of the same type and was reaccessing invalid elements
* initial ui
* changed the group name
* groups counter in ui
* added operators for selection and breaking link in the ui
* small removal
* changed IFC operators to _execute
* added simples linked aggregate test
* small fix in remove_old_connections function
* added test for refresh linked aggregate
* refresh linked aggregates now preserves the objects original name
* small fix in recreate_connections function
* tests for Refresh Linked Aggregate
* test for Refresh Linked Aggregate after copying an object
* small deletion
* added custom incremental naming
* small fix in tests
* small fix on the number for renaming
as probably in the most cases user would want 1 style per 1 representation item
After this it's finally possible in BBIM to assign styles to representation items through the materials: https://imgur.com/a/cgiJ1KV
Example - https://i.imgur.com/Mk6mkuP.png
E.g. alt-click now opens .ifc directory and shift-click opens .ifc with default software associated with .ifc files.
Should be cross-platform but tested only on Windows
Added this code to tool.Blender so it can be reused for other operators invoking file browsing window.