add googleusercontent
Do not use RangeFetch for 'HEAD'
Merge pull request #196 from harmonymeow/no-head

Do not use RangeFetch for 'HEAD'
dont cache socket when do_CONNECT_FWD
cache socket according ssl connection time
bump version to 3.1.1
Merge branch '3.0' of https://github.com/goagent/goagent into 3.0