tutorial_app: replaced deprecated send_file
tutorial_app: replaced deprecated send_file

Replaced the deprecated statement send_file with the static_file statement,
since send_file does not exist in the current development version.

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