add VCFCollectionAdaptor
add fetch_all_by_name_list method
adaptor for VCFCollection, reads configuration from JSON config file
new module VCFCollection, provides access to a set of VCF files via EnsemblIO
sample config file for VCFCollectionAdaptor
rudimentary first stab at code to use VCFCollection in place of DB to fetch genotypes
retrieve IndividualGenotypeFeatures instead of IndividualGenotypes, lazy-load VCF object on demand
export CONFIG_FILE variable so it can be set externally
add support for use_db, creating populations from panel structure defined in config
allow new without DB via using eval, change a key name
only create genotypes on VariationFeature objects
restrict to individual names within IO VCF parser for speed
method name changed
add use_vcf method

Conflicts:

	modules/Bio/EnsEMBL/Variation/DBSQL/DBAdaptor.pm
big reorganisation, allow proper use of VCF
add a bunch of new methods, some speedups
allow config file to be set as ENV variable
support fetching LD populations from VCFCollection
add population_prefix, failsafe if no collections loaded
change defined to exists