fix for #39 Pile.mouse_event error on empty pile
fix for #39 Pile.mouse_event error on empty pile

rndusr/urwid,harlowja/urwid,wardi/urwid,hkoof/urwid,harlowja/urwid,hkoof/urwid,wardi/urwid,inducer/urwid,drestebon/urwid,ivanov/urwid,foreni-packages/urwid,urwid/urwid,foreni-packages/urwid,urwid/urwid,drestebon/urwid,rndusr/urwid,hkoof/urwid,inducer/urwid,inducer/urwid,urwid/urwid,douglas-larocca/urwid,wardi/urwid,rndusr/urwid,foreni-packages/urwid,douglas-larocca/urwid,harlowja/urwid,tonycpsu/urwid,ivanov/urwid,tonycpsu/urwid,tonycpsu/urwid,ivanov/urwid,drestebon/urwid,douglas-larocca/urwid