added a method getFTP() to return a sftpClient for use in RemoteBinaryData to check the size of remote bnt and bed files
added a method getFTP() to return a sftpClient for use in RemoteBinaryData to check the size of remote bnt and bed files

wtsi-medical-genomics/evoker,wtsi-medical-genomics/evoker,wtsi-medical-genomics/evoker