added sortv option to mergebed
added sortv option to mergebed

4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront