Time for a small update of Todour.

• Potential bug for writing files fixed (flushing seems at times not happening on virtual filesystems)
• Added documentation on GitHub pages
• Added support for treating due as threshold
• Added support for “business days” https://github.com/SverrirValgeirsson/Todour/issues/31
• Updated QtAwesome to a newer version
• Changed name of icon files to todour.* from newicon.*

As always, you will find the downloads on https://nerdur.com/todour-pl/