add style object basics from music21

[mscuthbert]

lets .style.hideObjectOnPrint work on clefs, ts, ks.

Leaves extra space on the Stream however for the hidden objects. A to-do for later

[jacobtylerwalls]

Super!

Some nitpicks you can feel free to ignore.

Leaves extra space on the Stream however for the hidden objects. A to-do for later

I'm not sure we need to bother. Setting .renderOptions.displayTimeSignature = false should take care of the spacing issue (as well as display, without having to resort to hideObjectOnPrint AFAIK). If someone wants to hide something, I think intuition could cut either way re: whether to alter the spacing--someone might want to just drop in their own element at that location.

[mscuthbert]

Right now, the issue is that renderOptions.displayClef gets overwritten every time the Stream's position is recalculated, so until we separate out renderOptions from style, we can't just rely on users setting renderOptions.

[jacobtylerwalls]

renderOptions.displayClef gets overwritten every time the Stream's position is recalculated

Ah right, okay, sounds like #135. Got it.