Record current replace string as part of macro find action

Previously we would only record it if the user invoked a replace action from the find dialog, but the user may invoke “find” from the dialog and then subsequently “replace” via keyboard/menu (where we would not record the string).
Find macro actions now populate the search/replace pasteboard

This should be consistent with TextMate 1.x and is required for the replace actions.
Update Onigmo submodule
Let editor_t remember (regexp) captures from editor_t::find
Implement kReplace / kReplaceAndFind actions

These are used when replaying macros.
Use temporary pasteboards when replaying macros

This applies to search, replace, and (unless disabled) regular pasteboard.
Avoid detached objects in core data store