Add explicit warning if no group/testcase specified on command-line
Add explicit warning if no group/testcase specified on command-line

Ensembl/ensj-healthcheck,thomasmaurel/ensj-healthcheck,Ensembl/ensj-healthcheck,Ensembl/ensj-healthcheck,thomasmaurel/ensj-healthcheck,thomasmaurel/ensj-healthcheck,thomasmaurel/ensj-healthcheck,Ensembl/ensj-healthcheck