Parse ASCAT and bb output directories to load CNA data

See "annotate_copy_number" func A function required to load copy number for a tumour sample from camdac, either ascat or bb, result should be: chrom, start, end, nA, nB, CN (total), seg_min and seg_max. This should also include the purity and ploidy. As a separate list? note that seg_min and seg_max are actually duplicates of the start and end columns, required to keep track of the ascat segment positions after overalp WARN: This drops sex chromosome but not implimented. Also should drops CN=0 (hom del) regions

load_cna_data(tumour, config, data_type)