Ensure edit line in ctkConsole is always visible

Even when the line is 2 line long.
Also, on Mac, typing Control (not Command) was resetting the cursor
to be at the end of the document.

Closes #295
Merge remote-tracking branch 'finetjul/295-ctkconsole-ensure-lines-visible'

* finetjul/295-ctkconsole-ensure-lines-visible:
  Ensure edit line in ctkConsole is always visible