Allows the user to apply the current curation to the analyzer, creating a new analyzer in memory.

What this PR does:

• When the user clicks the apply_curation button, we create a new, curated analyzer in memory. All views are _reinitialized and the CurationModel is created and stored in controller.applied_curations and the current curation is cleared. Now the user can start curating again.
• Adds _reinitialize method to all Views, allowing the view to update when the analyzer is updated (might also be useful for re-computations!)
• Allows the user to save multiple curations as a SequentialCuration.

I think this is pretty much done!

To do:

• add to panel
• save original analyzer without extensions somewhere
• keep track of the chain of curations (must add new_unit_ids)
• ensure properties are properly kept track of
• ensure colours are properly kept track of
• be able to save multiple curations
• allow user to undo apply(??)