titleTemplate, mmap output buffers, new http/email fields

* titleTemplate config option (issue #229)
* output buffers are now mmaped so they are more likely to be returned to OS
* free output buffers are now cached, controlled by maxFreeOutputBuffers
* More untagging, new fields http.method, http.statuscode, http.bodymagic
* More untagging, new fields email.bodymagic