Minor overhauling.

browse: take advantage of new dwm-athens control stuff (dwm -x):
  -w            Always open a new firefox window.
  -a <pattern>  Try to find an existing instance which title matches the pattern.
                If found just activate it. If not open the url in a new window.
  Default:      Try to find a visible (i.e. in current tagset) firefox instance.

launchers, viewmd, etc. adapted to new browse interface.

bash refactoring: new convention: if <cond>; then, while <cond>; do, etc.