GridFlow: use width_type and 'given' instead of width_calc and 'fixed', for consistency with other containers
GridFlow: use width_type and 'given' instead of width_calc and 'fixed', for consistency with other containers

--HG--
branch : feature-containers

wardi/urwid,inducer/urwid,urwid/urwid,harlowja/urwid,hkoof/urwid,bk2204/urwid,rndusr/urwid,harlowja/urwid,harlowja/urwid,ivanov/urwid,Julian/urwid,foreni-packages/urwid,tonycpsu/urwid,drestebon/urwid,douglas-larocca/urwid,foreni-packages/urwid,hkoof/urwid,inducer/urwid,wardi/urwid,ivanov/urwid,zyga/urwid,Julian/urwid,mountainstorm/urwid,mountainstorm/urwid,zyga/urwid,bk2204/urwid,douglas-larocca/urwid,westurner/urwid,drestebon/urwid,drestebon/urwid,mountainstorm/urwid,zyga/urwid,urwid/urwid,Julian/urwid,wardi/urwid,rndusr/urwid,rndusr/urwid,hkoof/urwid,douglas-larocca/urwid,tonycpsu/urwid,inducer/urwid,urwid/urwid,bk2204/urwid,foreni-packages/urwid,westurner/urwid,westurner/urwid,ivanov/urwid,tonycpsu/urwid