Can't use limma model without Covariates

Hi !

When launching the differential analysis after letting the input$coVar empty. I get the following error :

`Error: "length of 'dimnames' [2] not equal to array extent.`

So what if the user do not have any co-variates in his analysis ?  Is it possible ? If not, is it because of unrelevant statistical analysis purposes ? 

Thanks you in advance for your help !

Best,
Clément