trapped dbi errors in try/catch block, so handled same as other VEP.pm errors; replaced NGS::MooX::Types with Local::MooX::Types; changed existing_variation col in vep_data & sample_data tables to TEXT due to entry >255 chars

separated hmds_ref into request_number & year for ease of order by on sample data retrieval

extended download function to sample data, split existing vep & non-cds downloads into separate files; moved update_vep_table() function into new save_data() method

moved all db queries to NGS::DB; added download facility for processed data; new MySQL ngs db for download data