Consolidate camera/transform state with style state

[anandthakker]

As a followup to smart setStyle, move the camera state management into Style (perhaps renamed to StyleState a la #3650), so that camera state can be included as a top-level property to Map#setStyle (and Style#setState).

• Accept camera/transform state as top-level setState property (includes zoom, center, pitch, bearing, minzoom, maxzoom, lngRange, latRange)
• Move transform-mutating stuff from Camera to Style
• Refactor Camera methods to use Style#setState
  • tricky thing here is transitions; can Camera's multi-frame easing code be reworked to use setState efficiently?

I think the second and third steps here may become much simpler after #3583

[jfirebaugh]

I think we should keep Style and Camera as separate state. Typically one does not want the camera to change when changing the style. In the uncommon case where you do, you can simply make two method calls.