BaseResponse cleanup.
BaseResponse cleanup.

All BaseResponse classes now support a 'headers' argument that
accepts a dict or a list of header/value pairs. For BaseResponse
and HTTPResponse, this is the third positional argument.

StdioA/bottle,catroot/bottle,mefyl/bottle,wangjun/bottle,SmithSamuelM/bottle,SamuelMarks/bottle,gaotongfei/bottle,oz123/bottle,xsank/bottle,ifduyue/bottle,AWFU/bottle,SamuelMarks/bottle,defnull/bottle,ListFranz/bottle,hayate/bottle,myzhan/bottle,ericfrederich/bottle,kevinmel2000/bottle,wangjun/bottle,samstav/bottle,ifduyue/bottle,fkazimierczak/bottle,ericfrederich/bottle,bottlepy/bottle,defnull/bottle,mrdon/bottle,enzzc/bottle,ListFranz/bottle,bottlepy/bottle,khirayama/bottle,fkazimierczak/bottle,taisa007/bottle-ja,hkmshb/bottle,gaotongfei/bottle,prologic/bottle,StdioA/bottle,prologic/bottle,catroot/bottle,AWFU/bottle,Kjuly/bottle,kevinmel2000/bottle,kevintaw/bottle,CentricWebEstate/bottle,samstav/bottle,mrdon/bottle,oz123/bottle,enzzc/bottle,Inndy/bottle,Kjuly/bottle,hkmshb/bottle,SmithSamuelM/bottle,myzhan/bottle,Inndy/bottle,khirayama/bottle,kevintaw/bottle,hayate/bottle,taisa007/bottle-ja,CentricWebEstate/bottle,mefyl/bottle