revert Function._expressions / _replacements changes
revert Function._expressions / _replacements changes

inclement/vispy,dchilds7/Deysha-Star-Formation,jay3sh/vispy,ghisvail/vispy,QuLogic/vispy,hronoses/vispy,drufat/vispy,sh4wn/vispy,hronoses/vispy,ghisvail/vispy,Eric89GXL/vispy,inclement/vispy,hronoses/vispy,Eric89GXL/vispy,srinathv/vispy,QuLogic/vispy,jdreaver/vispy,julienr/vispy,RebeccaWPerry/vispy,RebeccaWPerry/vispy,jdreaver/vispy,michaelaye/vispy,michaelaye/vispy,julienr/vispy,RebeccaWPerry/vispy,sbtlaarzc/vispy,dchilds7/Deysha-Star-Formation,michaelaye/vispy,julienr/vispy,kkuunnddaannkk/vispy,bollu/vispy,QuLogic/vispy,jdreaver/vispy,sh4wn/vispy,kkuunnddaannkk/vispy,kkuunnddaannkk/vispy,jay3sh/vispy,sh4wn/vispy,bollu/vispy,sbtlaarzc/vispy,jay3sh/vispy,srinathv/vispy,drufat/vispy,srinathv/vispy,ghisvail/vispy,inclement/vispy,dchilds7/Deysha-Star-Formation,drufat/vispy,Eric89GXL/vispy,bollu/vispy,sbtlaarzc/vispy