Tracking developments in tidalcycles/strudel#1207

Tweaks to do along the way

• polymeter should fit a cycle, the lowest common multiple being the step count. This should probably apply in mininotation to {} as well
• As @matthewkaney pointed out, step count of euclid should be used e.g. "x(3,8)" should have step count of 8
• Look at bringing back old 'preplace' functionality, ref Preplace update #718