Fixes a panic when AddGroup isn't called before AddCommand(my-sub-command) is executed. This can happen within more complex cobra file structures that have many different inits to be executed. Now, the check for groups has been moved to ExecuteC and provides more flexibility when working with grouped commands - @marckhouzam (and shout out to @aawsome, @andig and @KINGSABRI for a deep investigation into this! 馃憦馃徏)
