Show favorite bookmark in main-screen (highlighted)
Add baseline-reset when main screen is shown or when the favority
bookmark is searched.
Some code cleanup
Add the concept of a query results baseline, i.e., the result for
bookmark-queries at some particular point in time. Later, we can compare
the results with the then-current query-results.
Show the delta in the main view. Add mu4e-reset-baseline-query-results
to reset the baseline to 'now'. By default, we automatically reset when
explicitly (interactively) going to the main-view, i.e., M-x mu4e.
Fire mu4e-index-updated-hook after any index operations, where anything changed
or not. Add a new variable `mu4e-index-update-status' which can be used to see
what changed (if anything) in the last indexing operation.
Keep mu4e-message-changed-hook in place; it only fires when a message
changed (and when it is update).
Remove the long-obsolete `mu4e-msg-changed-hook'.
Usurp more of the utils code than can be re-used without further dependencies in
helpers.
Split off specific parts in their own file.
After the helper/utils changes, update the rest of mu4e to take the changes into
account.