version 2.9.5
- Corrected a bug in function hyperGeoTest to avoid significant p-values for 
zero observed hit
version 2.9.4
- Correct a contradiction in annotationConvertor. Now it can convert between 
entrez genes and non-entrez genes.
version 2.8.1
- the dependency to igraph was changed to igraph0
version 2.5.1
- added an attribute 'geneSetSize' to enrichment map in function 'viewEnrichMap' 
  so that the user can rescale the size of gene sets by themselves
- added a new argument 'plot' to function 'viewEnrichMap' so that the user can 
  control whether or not to plot the enrichment map
