[ENSCORESW-262]. Customised the Exon summary as hash, gene and transcript...

[ENSCORESW-262]. Customised the Exon summary as hash, gene and transcript summaries have been improved. Biotype mapper can ask objects for their SO term and knows Variation objects are already annotated with a code. BioType mapper caches SO retrieval so it is a massive speed increase for large result sets.