Added new DictProperty, lazy_attribute and cached_property helpers.
Added new DictProperty, lazy_attribute and cached_property helpers.

(Use with care, test cases are still missing)

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