Re-design staff props and staff type props dlg boxes.

- Staff props dlg: added type props common to all types (num. of lines, line dist., etc.).
- Changing some type props but canceling the main dlg no longer changes the staff type.
- Fixed equality checks in EditStaff::apply().
- Both dlgs: set all buddies and proper tab order.

Also:
- Staff group names ("Standard", "Percussion", "Tablature") made uniform in spelling and translatable.
- Fixed Instrument::operator==().
Updated EditStaffType. Improved EditStaff.
Align code to commits merged in the meantime.
Fix staff type group names in score files.
Align with latest enum changes
Do not select any template at EditStaffType initial opening.
Layout of score for TAB preview made more compact.
fix sforzato accent positioning
Merge pull request #937 from mgavioli/Staff_props_and_stafftype_props_dlg_box_redesign

Staff props and stafftype props dlg box redesign
make enum class SegmentType a ": short"
convert enum Hidden into global enum class

after having seen how it is done in e1b1246
convert enum AlignmentFlag into enum class
small step further in converting enum Repeat into enum class

not there yet, as at least overloaded operators for |, &, |=, &= and ~ would be needed to make this fully working. And even then it'd require lots of explict casting. This is most probably not be worth the price...
convert enum ElementFlag into enum class
convert enum LayoutFlag into enum class
convert enum ArticulationShowIn into enum class
convert unnamed enum into enum Col

making it a class, just to cast back to int, is not worth the effort
convert unnamed enum into enum class State
convert unnamed enum into enum AmbitusControl

making it a class, just to cast back to int, is not worth the effort
convert unnamed enum into enum ImageControl

making it a class, just to cast back to int, is not worth the effort