New features and changes since tin-2.6.0

New features
------------
- pcre2 support (configure --with-pcre2-config[=PATH] vs.
  --with-pcre[=PATH])
- NNTPS support based on libressl/gnuttls/OpenSSL (RFC 8143)
  (configure --with-nntps[=[libtls|openssl|gnutls]])
- "COMPRESS DEFLATE" support (RFC 8054)
- allow to cancel wait_message() via key press
- option to hide help/mail-info in title: show_help_mail_sign
- option remove SOFT HYPHENs (U+00AD) from non verbatim blocks:
  suppress_soft_hyphens
- ConnectionInfo page ('J') incl. TLS connection info
- ${TIN_HOMEDIR:-"$HOME"}/.tin/$NNTPSERVER${NNTPPORT:+":$NNTPPORT"}/msglog
- -t timeout cmd.-line option
- :port suffix in newsauth, newsrctable and -g
- -[zZMN] now note unsubscribed cmd-line groups
- cmd. execution via ! for x_body
- mime encode and fold long header-lines (> 998 octets) if !post_8bit_header
- post f'up from thread-level ('f' and 'F')
- configurable display format of attachments
  (page_mime_format, page_uue_format, attachment_format)

Changes
-------
switch from stdio to own buffer implementation

Retired Features
----------------
