Updated multisample.vcf

Updated header and sample names to be more informative/clear
Update multisample.feature

Changed file to correspond to the updated vcf file
Update README.md

Suggested sample renamening according to updated multisample.vcf
Merge pull request #1 from jdeligt/patch-1

Update README.md
Fixing tests
Adding/removing tests
More fixes
Add tests for missing samples
Add to README
Support for missing_samples?
Add missing_method for sample check
Better place for creating the sample_index
This works:

  ./bin/bio-vcf --filter "rec.original?" < test/data/input/multisample.vcf
Moved empty sample test to module
Added support for

./bin/bio-vcf --filter "rec.sample.original?" < test/data/input/multisample.vcf
Step
Fixing Joep tests
Fixing Joep tests
More tests
All tests pass