Style of the initial bar line of a system.

In some engraving styles (mainly jazz), a double system initial bar line is used at structural articulations of the piece.

The PR supports this style, by adding a `_systemInitialBarLineStyle` variable to the `Measure` class which controls the style of the system bar line when the measure is the first of the system and by default it is set to NORMAL. This variable is not accessed directly; rather it is controlled by manipulating the system bar line. A system bar line can be edited:

- by dropping on it a bar line style from the palette (structural styles, like any repeat or END are ignored);
- by selecting it and double clicking a bar line style from the palette (same note as above).

It can be reset:

- by undo;
- by dropping on it (or selecting and double clicking) a NORMAL bar line style from the palette;
- by selecting and deleting it.

As the system bar line style is stored in the measure, if the first measure of a system changes (because of some other editing), the system bar line style will follow accordingly.
fix #32651: Naturals should not be shown at system break
add gui scaling option -x
save custom workspaces without scaling (apply on load)
fix #33016: bad text size with spatium scaling in 1.3 scores
fix #35661: bad breath position if no tick tag
fix #30011: crash on delete of staff with cross staff note
fix #6369: Pasting repeat bar over barline corrupts measures. Also fix navigation through repeat measure, and range selection end on repeat measure
fix #34496
Merge pull request #1480 from MarcSabatella/40011-delete-staff-with-cross

fix #30011: crash on delete of staff with cross staff note
Merge pull request #1478 from MarcSabatella/33016-text-scale-13

fix #33016: bad text size with spatium scaling in 1.3 scores
fix #40056: Crash by selecting twice or once all similar elements
spelling mistakes, remove ? button in start center
fix #39801
fix some strings
Merge pull request #1481 from Jojo-Schmitz/pre-translation

fix some strings
fix #34006
revert to multimeasure
Merge pull request #1479 from MarcSabatella/35661-breath-tick

fix #35661: bad breath position if no tick tag
Merge pull request #1464 from MarcSabatella/scaling

add gui scaling option -x