Fixes to serveFile:     · include DEL in the test for unprintable characters     · call Stat() on the already-opened file (to save a       potential walk in the kernel)     · reduce the number of conversions from int to string
Fixes to serveFile:
    · include DEL in the test for unprintable characters
    · call Stat() on the already-opened file (to save a
      potential walk in the kernel)
    · reduce the number of conversions from int to string

redhotpenguin/web,epigos/web,fredatgithub/web,hraban/web,devfreesg/web,yjp211/web,williamzhang2013/web,ginashi/web,zouchao2010/web,riversea2015/web,no2key/web,tempbottle/web-1,mattn/web,hoisie/web,mapix/web