[BioC] Many missing GO terms from GOHyperG call using mgu74av2

[Francois Pepin]

> Unless we build the annotation packages frequently (every week?), there will be 
> descripancies. You may try to build your own annotation packages to minimize the 
> descripancies.  

Is there a reason why that wouldn't be a good idea? I personally like
having the latest annotations. I can see a problem trying to reproduce a
given analysis, but old annotations can be kept around for a while.

How often are the metadata packages being rebuilt right now? What
decides when they're being rebuilt?

Francois