performance wishlist

[ryanberckmans]

• Render multi-line input instead of String.split'ing it first. Right now, AnsiColorStream.pushRaw(rawText) calls split("\n") prior to feeding the lines individually into renderDOMLine. There is no reason we can't render multiple lines in the same call, so long as the return value is an array of [domLine]. (The design goal is to have count indicate number of lines in scrollback, and to pair clearTextLine with domLine for scripting.)