Evaluate mean correlation between residuals in gene set based on results from dream
     
    
    Usage
    corInGeneSet(fit, idx, squareCorr = FALSE)
 
    
    Arguments
    - fit
- result of differential expression with dream 
- idx
- indeces or rownames to extract 
- squareCorr
- compute the mean squared correlation instead 
 
    
    Value
    
list storing correlation and variance inflation factor