To be addressed in 7.29
=======================

310 - a new authentication callback

312 - custom Content-Length appears in CONNECT, solve it by offering a
      separate option to provide headers for the CONNECT request:
      http://curl.haxx.se/mail/lib-2012-09/0059.html

317 - CURLINFO_SSL_TRUST to return SSL-specific data for a darwinssl build

322 - pipelining improvements

327 - 
