Merge branch 'release-0.21' into develop
Added example for connection handling.
Merge branch 'hotfix-0.22' into develop
Cleaned up examples source code.
Updated incomplete documentation for the on_message callback.
Fixed bug in on_message callback.
Fixed bug in DESTROY subroutine.
Made the on_message callback less strict.
Minor fix in get_uuid subroutine.
Increased version number to 0.23 and documented changes.
Merge branch 'release-0.23'