1.6.1

• Add uuidmap for mapping UUIDs to pointer values

• Added fs_matching_subdirs and fs_matching_subdirs_regex for finding matching subdirectories

• Change object map to use external ID and ref count representation for object, allowing
  pointers to any type to be stored in map. Rename the objectmap_lookup_ref and objectmap_lookup_unref
  to better named objectmap_acquire and objectmap_release

• Rename library_unload to library_release to match object map function naming

• Bugfix on macOS/iOS where main thread did not properly initialize memory subsystem if
  other than the default system was used

• Add thread_is_entered to query if thread_enter has been called on the calling thread

• Bugfix in macOS file system watcher, correctly bootstrapping thread memory handling for cleanup
  if needed

• Fix path_base_file_name to return name up to last dot in filename, not first dot. A file "path/to/foo.bar.ext" will thus return "foo.bar" instead of "foo"