This release adds the Variant Call Format (VCF) to its possible output options. To select it, just pass the option --vcf. The file is output to the standard-out. So you can run something like
samtools mpileup ... | pileupCaller --randomHaploid -f <snp_file> --vcf > output.vcf
You can also zip the output, by chaining it through gzip -c:
samtools mpileup ... | pileupCaller --randomHaploid -f <snp_file> --vcf | gzip -c > output.vcf
Please take a look at the README, which has been updated.