Cumulative changes patient-network since candidate-gene refactoring

- Candidate gene support included (apparently still not fully merged in from other pull request)
- Simplified patient similarity scoring
- Fixed logging calls
- Removed code used to dispatch Exomiser from within Java (was a mess, anyway)
- Switched to simpler representation/caching of genotype data
- Added full support for patient cache clearing
- Added draft Exomiser dispatch script