update docs to reflect CSS selector support for more elements
update docs to reflect CSS selector support for more elements

vveliev/page-object,marxarelli/page-object,irfanah/page-object,cheezy/page-object,jkotests/page-object,cheezy/page-object,bootstraponline/page_object,ducthanh/page-object,pvmeerbe/page-object,marxarelli/page-object,ducthanh/page-object,drodriguezaltimetrik/page-object,drodriguezaltimetrik/page-object,morozgrafix/page-object,pvmeerbe/page-object,bootstraponline/page_object,titusfortner/page-object,Donavan/page-object,jkotests/page-object,titusfortner/page-object,vveliev/page-object,irfanah/page-object,morozgrafix/page-object,Donavan/page-object,SpencerMalone/page-object,SpencerMalone/page-object