add example chat

1. session move from astaxie/session to beego/session
2. support 4 type session

1. Router
2. SetSession/GetSession/DelSession
3. RenderString
4. str2html/htmlquote/htmlunquote
5. move the template Function to util.go

add func Html2str()

Fix a wrong logical for AddFuncMap method.

Fix wrong method name call for FilterPrefixPath.

add fcgi support

Refactor pprof.go to use switch instead of if/else

http support pprof
PprofOn set to true you can profile the runtime data.
template add date func like php's date function

{{date "Y-m-d H:i:s"}}