v2.3.15—we're taking the atm with us to mexico

This is the first Notcurses release that builds on Windows, though Windows support is still very experimental.

• Terminals which invert cursor reports are now detected in all modes, and accounted for #1886
• Terminals which 0-index cursor reports are now detected in all modes, and accounted for #2044
  • This fixes notcurses-info output in kmscon
• notcurses-tester now only requires 50 columns to run, down from 80 #2042
• Loop on EBUSY and EWOULDBLOCK in control_read(), eliminating some initialization failures, thanks @christianparpart !
• Properly hold fixed subplanes where they are on parent plane scroll #2036
• Implement terminfo k*n input sequences, so we no longer return error on ctrl/shift+special #2028
• Improve startup latency and unite direct/rendered mode startup #2023
• notcurses-info: simplify coloring
• Detect kitty graphics support via query #1998
• Merge in portable fbuf replacement for POSIX memstreams, necessary for windows #1977 , #2038
  • We now build and, to a degree, work on Microsoft Windows #463
• Lots of improvements for Linux framebuffer console graphics #2048
• Fix ncls path separation #2063