When re-writing measures, do not set bar lines as generated.

When measures are re-written, for instance after adding or changing a time signature, the bar liens of the re-written measures are unconditionally marked as generated.

Fix: the bar line status of the bar line of the first measure being re-written is replicated in the newly re-written measures.
Fix tests.

The time sig change test now no longer turns bar lines into generated: aligned the ref score.
Added test.

This PR is implicitly tested by tst_timesig and in fact:
- this PR required adjusting the timesig test
- this test uses a copy of the same score 01 of tst_timesig and does on it exactly the same operations.

However, a specific test has been added to test for specific bar line parameters and to issue more specific messages.