Fix crashes from unchecked uses of lua_tostring. Closes #1588.
Select the contents of the find box when opening the search/replace dialog
Fix the option name for the subtitle MRU list. Closes #1592.
Remove the 'Collisions' setting from the properties dialog

No renderers actually support it so there's really no reason for it to
be settable.
Strip Collisions lines on read

Nothing supports them and malformed values crash VSFilter.

Closes #1583.