Log Message:
Update to 0.1.1:

libvisio 0.1.1

- Fix a minor issue reported by Coverity.
- Check arguments of public functions. Passing NULL no longer causes
  a crash.
- Set a minimal thickness for arrow markers to ensure they are visible.
- Fix a crash when reading a broken file, found with the help of
  american-fuzzy-lop.
- Use symbol visibility on Linux. The library only exports the two public
  functions now.
- Import document metadata (fdo#86664).