quadratic curve bounding box bug fix
quadratic curve bounding box bug fix

skyujilong/zrender,ecomfe/zrender,noikiy/zrender,armslave00/zrender,dato-code/zrender,uooo/zrender,elancom/zrender,laomu1988/zrender,noikiy/zrender,powy1993/zrender,uooo/zrender,stanleyxu2005/zrender,ChaosPower/zrender,ekinwei/zrender,nagyistoce/ecomfe-zrender,lkiarest/zrender,ilovezy/zrender,IveWong/zrender,coderstudy/zrender,coderstudy/zrender,armslave00/zrender,ChaosPower/zrender,jl9n/zrender,IveWong/zrender,ecomfe/zrender,jl9n/zrender,nagyistoce/ecomfe-zrender,skyujilong/zrender,lkiarest/zrender,elancom/zrender,ilovezy/zrender,powy1993/zrender,songshuang00/zrender,dasmond/zrender,ekinwei/zrender,dato-code/zrender,dasmond/zrender,KnightBubble/zrender,stanleyxu2005/zrender,laomu1988/zrender,songshuang00/zrender,powy1993/zrender,KnightBubble/zrender,ecomfe/zrender