POCO C++ Libraries Release 1.15.1 is Available

This is a bugfix and maintenance release that also introduces a few new features:

• PropertyFileConfiguration now supports an !include directive for composing
  configuration from multiple files, and preserves the original file layout
  (comments, blank lines, key order) when saving changes.
• ProcessRunner gained a PROCESS_KILL_TREE option for terminating entire
  process trees on supported platforms.
• clang-cl is now supported as a build compiler on Windows.
• LoggingConfigurator can now create fully configured loggers at runtime.

All bundled third-party libraries have been upgraded to their latest releases,
including security fixes for libexpat, libpng, zlib, and utf8proc.

For details, please see the CHANGELOG.