Major performance improvements in console and TX/RX flash

[2fast2fourier]

What's this PR do?

This PR fixes two major performance hits when running a program that has very fast debug output. The first is to simplify the RX/TX flashes to avoid triggering expensive React changes. The second is to rework console output updating to avoid expensive scroll operations and has the additional benefit of allowing smooth scrollback even as more data comes in.

What are the important parts of the code?

The scroller.js class in the editor plugin contains the receive pane update logic which controls the majority of the scrolling logic. The indicators.js class contains the new RX/TX logic.

How should this be tested by the reviewer?

Run a fast-loop debug program at various speeds, try to scroll back the window and see how it functions. Verify the window will re-enter 'sticky' mode when scrolled to the bottom of the screen.

Is any other information necessary to understand this?

This fixes a major performance issue on older chromebook devices by reducing the redraw/scroll events within the receive pane.

What are the relevant tickets? (Please add closes, refs, etc)

Closes #178

[2fast2fourier]

A simple fast-debug-loop:

'{$STAMP BS2}
'{$PBASIC 2.5}

Idx VAR WORD

'Set this to 10, 100, 500 and test scroll-back.
Delay CON 10

Idx = 0

DO
  Idx = Idx + 1
  DEBUG "Loop ", DEC Idx, CR
  HIGH 0
  DEBUG "On",CR
  PAUSE Delay
  LOW 0
  DEBUG "Off",CR
  PAUSE Delay
LOOP

[phated]

should be function Scroller(){ so you don't have an anonymous class

[phated]

ints here are just shortcuts to px styles, but this is fine