updated backend tests to exclude new mouse methods.
updated backend tests to exclude new mouse methods.

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