Made tube __init__ return valid vertices
Made tube __init__ return valid vertices

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