Merge branch 'features/JAL-4134_use_annotation_row_for_colours_and_groups' into develop

major improvements: JAL-4134 column tree is only computed when requested. group colours on PAE matrix row can be hidden.
JAL-1556 new popup menu options to select/colour by annotation row.
JAL-4089 selected columns used to (re)compute superposition
JAL-4190 escape in tree panel clears active selection
JAL-4182 patch fixes copy of annotation for sub-sequence
JAL-4177 patch fixes add view/new view not being disabled when loading structures from local file via structure chooser
JAL-4123 outstanding work to make 'default' do the right thing when a model is imported manually and a PAE is also provided.