Closes GH-315 KeyPressEvent generates error message
Closes GH-311 database.py not using logging facilities
GH-313 Link to online documentation from within the application

- Adds a Help link to the online docs under Help > Online Documentation
Closes GH-295 Freeseer Exception when talk database is empty

- When no database present default to a title of "default"
- Fix issue when stopping a recording with no event and room set
Merge branch 'experimental' of https://github.com/Freeseer/freeseer into multiaudio-mixer
Update license for multiaudio mixer