sort genomic data

 gsort is a tool to sort genomic files according to a genomefile.
 For example, to sort VCF to have order:
 X, Y, 2, 1, 3, ... and the header needs to be kept at the top.
 .
 As a more likely example, if a file nneds to be sorted to match GATK
 order (1 ... X, Y, MT) which is not possible with any other sorting
 tool. With gsort one can simply place MT as the last chrom in the
 ".genome" file.
 .
 It will also be useful for getting files ready for use in bedtools.