The multiline progress bar would not clear itself before writing to stdout,
leading to interference with the redraw; the most visible symptom is after
building in the repl, where the lines indicating the build outputs would be
wiped instead of the progress bar header. Separate the steps of erasing and
redrawing the progress bar, so that arbitrary output can happen in between in
a non-awkward way. In addition to fixing the bug, the code is simplified.
Change-Id: I142cf38f5ba5cd672cd6016e996b2f7bf726e9cd
Alois Wohlschlager
0b2d58a925