PR comments - refactoring

Change validate method of ICommandParameter to returns IFuture<boolean> as some of the implementations of the method are using IFuture calls, so we have to be consistent. This leads to change in the return type of validateMandatoryParams, validateCommandArguments definitions to return IFuture<boolean> as well. Add executeCommandAction method to remove duplicate code.  Multiple smaller fixes (spelling errors, indentation issues, etc.).