Allow more than one one-char command in rigctld
E. g. CQRLOG sends fmv to rigctld, split that to f m v and execute all commands. +f+m+v will be split to +f +m +v.
E. g. CQRLOG sends fmv to rigctld, split that to f m v and execute all commands. +f+m+v will be split to +f +m +v.