Various improvements I had locally on my branch
- Add find retainer by address, precisely find retainers of a specific closure address.
- Add ArrWords count analysis which performs a census of the ArrWords closures.
- Generalise display pane, to allow displaying trees of different types (not just ClosureDetails) (used by the arr words census)
- Allow commands to not have key bindings (and just appear in command picker)
- Cleanup: Remove "Analysis" modes such as dominator and size analysis.