clean up string conversion functions
Workaround for missing 'Rect' entry in annotation dictionaries (issue 4537)
Merge pull request #4512 from fkaelberer/cleanUpStringConversion

Clean up duplicate string conversion functions
Merge pull request #4539 from Snuffleupagus/issue-4537

Workaround for missing 'Rect' entry in annotation dictionaries (issue 4537)