Change to generic tvgids epg source

Change to generic tvgids epg source

- Refactor EPGSource to be generic (not TvGids-specific)
- Add timestamp to stdout and xmltv output
- Use generic TvGids instead of legacy classes
- new config file format 4
- store hsqldb database location in config file
- add --clear-cache option
- allow nice-time-milliseconds to be set using --configure