simplified args passed in NGS.pm method calls - src_data & data_file are equivalent so replaced all refs to former with latter; simplified config block in _parse()
wrapped call to NGS::VEP in try/catch to handle die via 500.tt - works for tests as well; test for invalid filename; display list of valid filenames in upload page
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
