Version 1.5.2

Added

• Add missing two-parameter version of pbf_message::next() function.
• Add data_view::empty() function.
• Add missing versions of add_bytes(), add_string(), and add_message()
  to pbf_builder.

Changed

• Clarify include file usage in tutorial.
• Updated included Catch unit test framework to version 1.9.6 and updated tests to work with the current version.
• Make some constructors explicit (best practice to avoid silent conversions).

Fixed

• Important bugfix in data_view equality operator. The equality operator is actually never used in the protozero code itself, but users of protozero might use it. This is a serious bug that could lead to buffer overrun type problems.