version 0.99.2
-bidirection flag added to simpleScore() function
-optimise generateNull() function
-change GSEABase from import to Depends
version 0.99.3
-change argument name bidirectional to knownDirection, default as TRUE

version 0.99.5
- represent expression data in SummarizedExperiement dataset
- function input checkings 
- R code re-organised

verion 0.99.8
- vectorize getPvals
- make toy_epxr_se

version 0.99.9
- remove internal keyword from generateNull