Port code to python3 and add parallelization per individual

[florealcab]

We port svtyper to python3.

We add svtyper-pms script which will parallelize by individuals (instead of parallelize by batch for an unique individual, like svtyper-sso). This script will launch in parallel the genotyping of 1 individual. Then, it uses bcftools to merge all VCF.

Due to python3 conversion, some tests failed. It looks like the difference is due to impact of taking the interger part for sum of floats of different precisions. Details in join file:

python3_python2_diff.txt