PEP8 compliance, bug fix in has_snp,deletion,insertion methods, new method geT_alt_lengths
Basic VCFReader class implemented. Bug fix in GFFReader contains with overlap=False, Fix in has_snp, deletion, insertion methods for VCFEntry where they will return a [False] list instead of [] for no alt alleles
Bug with overlap in VCFReader fixed, append_chromosome argument added to VCFReader, bug fix in getting size of longest VCF variant
Added basics of VCF support in incorporateGFF, added check for empty gff_objects in incorporateGFF