Removed Contributing topic from welcome page; fixed headings
Removed Contributing topic from welcome page; fixed headings

redhataccess/ascii_binder,redhataccess/doc_site_builder,redhataccess/doc_site_builder,Fryguy/ascii_binder,redhataccess/ascii_binder,nhr/ascii_binder,nhr/ascii_binder,Fryguy/ascii_binder,Fryguy/doc_site_builder