Bump version number for 0.5.2 release

Merge pull request totalopenstation#125 from steko/124-upref-missing-…

…file

Fix bug when configuration file is missing or empty

Release 0.5.0

Bump version to 0.4

Update PyInstaller instructions

Upgrade to v0.3.3 to fix a problem with the wheel distribution.

There were no other changes to the source.

Bump version number to 0.3.2

Bump version number

Bump version to 0.3