Less version 550

Version 550 was released on 17 Feb 2019.

These are the differences between version 530 and version 550:

• Add --mouse option.
• Add --wheel-lines option.
• Add --no-histdups option.
• Add --save-marks option.
• Support PCRE2 regular expression library.
• Redraw screen on SIGWINCH even if screen size doesn't change.
• Shell-escape filenames in history so they can be used again.
• Ring bell if user enters invalid long option name.
• Use PCRE_UTF8 flag for pcre regular expressions when in UTF-8 mode.
• Windows: use wide-char string to set console title.
• Don't count lines in initial screen if using -X with -F.
• Support mingw build system.
• Fix bug in v command on empty file.
• Fix bug in v command when filename contains shell metacharacters.