don't mention explicit version 7.8

 Things to do in project cURL. Please tell me what you think, contribute and

 send me patches that improve things!

To do for the 7.8 release:

To do for the next release:

 * Make SSL session ids get used if multiple HTTPS documents from the same

   host is requested.

 * Document the undocumented libcurl functions: the printf clones (like

   curl_msprintf, curl_mfprintf, curl_msnprintf, curl_maprintf and

   curl_mvfprintf), the string compare functions (curl_strequal

   and curl_strnequal) and the URL escape/unescape functions.

   curl_mvfprintf) and the string compare functions (curl_strequal

   and curl_strnequal).

To do in a future release (random order):