To be addressed in 7.28
=======================

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

315 - multiple receivers with SMTP and one fails

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

322 - pipelining improvements

326 - Improve testsuite for better results when running on MSYS/MinGW.
      Fix crahses with tests lib547, lib548, lib590 and curl.
      Fix socketflt for Win32. Fix hung with test 1326.

327 - 

