text in the start & end
text in the start & end

fixed https://github.com/ecomfe/echarts/issues/1136

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