Similar in range

This PR adds a new functionality: list selection of all elements of the same type that are in the current range selection.

I have tested the behavior for the following elements:
* spanner
* arpeggio
* chord symbol
* dynamic
* figured bass
* fingering
* fretboard diagram
* glissando
* lyrics
* tremolo

This will cause a crash for elements without a parent, which do not implement the virtual method. Would it be better to check for null, log, and return -1?