readVcfGT: split non-biallelic records rather then skipping

- Split non-biallelic records into biallelic records, filling in REF for "unseen" alleles

	```
	T	A,C	0|0	0|1	1|0	1|1	1|2	0|2	2|0	2|1	2|2
	```

	becomes

	```
	T	A	0|0	0|1	1|0	1|1	1|0	0|0	0|0	0|1	0|0
	T	C	0|0	0|0	0|0	0|0	0|1	0|1	1|0	1|0	1|1
	```

- add test for reading and writing a VCF
- treat haploid genotypes in the non-PAR region as diploid A/A
- convert tabs to spaces