Allow for zero length cache
Allow for zero length cache

Now cache is useful for volatile data too. (It 
still does parallel combining and body buffering)

tanveer12332/connect,dkfiresky/connect,redmantech/connect,redmantech/connect,khirayama/connect,chinazhaghai/connect,khalerc/connect,gtomitsuka/connect,behind2/connect,redmantech/connect,liuwei9413/connect,austincitylimits/connect,mi2oon/connect,llwanghong/connect,qitianchan/connect,mi2oon/connect,lian774739140/connect,brianloveswords/connect,davehorton/drachtio,senchalabs/connect,RoseTHERESA/connect,keenwon/connect,wghust/connect,RickyDan/connect