Need a whole pile of functions and events for measuring / scrolling

[jbt]

A few events and methods look like they're gonna be essential to implement nice chained scrolling in a side-by-side editor:

• Get the Y-position of a given line or collection of lines (also, how does this work with wrapping?)
• Scroll to a given Y position
• Get the current scroll state + view dimensions
• Fire events on scroll

All but the first one are of course possible with standard DOM events. Being able to measure to a certain line or collection without thrashing layout could be somewhat trickier.

[jbt]

Grabbing cursor position (both pixel x/y and character offset) too