Add setting for no accent on metronome

[jono grant 38]

There should be a checkbox for "don't accent bar" in the metronome settings. Or at the very least, if the user sets the same sound AND level for both first beat and other beats for their metronome, it should not accent each bar (It does).

Sometimes you have multiple time signatures happening and you don't want any particular accent in the metronome to confuse someone who is playing the odd time sig.

Jono