Updates Codemirror version to get rid of the freeze-on-triple-click bug.
Drag the output gutter to resize the editor and output windows.
Adds logic to better handle left/right/backspace/delete with selections.
Indent with four spaces working now.
Respects tabstops when calculating cursor position.
Fixes editor resize behavior on window resize, adds left border to output gutter to make dragging easier.
Handles left/right/backspace multiple selections.
Updates the editor with toggles to control compilation and stepping. Updates the error dialog to not block the viewport and to include a button to jump to the problem line in source.