Pending RELEASE-NOTES for the upcoming release

This is work in progress and will change before the release goes public on 2015-11-05.

Changes:

Bugfixes:

• curl_easy_getinfo: error code on NULL arg
• curl_mem_undef.h: limit to `CURLDEBUG` for non-memalloc overrides
• CURLINFO_FTP_ENTRY_PATH.md: this is for SFTP as well
• CURLOPT_MAXLIFETIME_CONN: make default 24 hours
• docs/libcurl: remove ancient version references
• easy_getinfo: check magic, Curl_close safety
• libcurl-security.md: mention long-running connections
• ngtcp2: check error code on connect failure
• quic: fix min TLS version handling
• quic: ignore EMSGSIZE on receive
• ssl-sessions.md: mark option experimental
• urldata: FILE is not a list-only protocol

Contributors:

Andrew Kirillov, Dan Fandrich, Daniel Stenberg, Emilio Pozuelo Monfort, Ethan Everett, fds242 on github, renovate[bot], Stefan Eissing, Viktor Szakats