Added multi-phenotype value and Hardy Weinberg Test

Phenotype field in *.ped can be any string
Hardy-Weinberg test for all samples, and groups of phenotypes
Customizable which phenotype is AFFECTED and UNAFFECTED
Prepared the report for the phenotype stats
ped.ragel accepts multiple phenotypes.
Implemented allele and genotype stats for each phenotype

Fixed default values for phenotype field
Fixed Bug in ped.ragel and ped_file.c
Added stats in phenotype_stats. Implemented phenotype-groups.

Improved stats report.
Merge branch 'next' of github.com:opencb-hpg/bioinfo-libs into multi-phenotype
Finished multi-phenotype stats.

Next: Change in all code the function get_variants_stats_tmp() to accept
	more parameters
Changed function call name for get_variants_stats_tmp()

Added num_variables arg wherever it was needed
Merge branch 'next' of github.com:opencb-hpg/bioinfo-libs into next
Merge branch 'multi-phenotype' into next
Merge branch 'multi-phenotype' into next
Merge branch 'next' of github.com:j-coll/bioinfo-libs into next
Support to VCF stats grouped by phenotype or other kind of variable