work on pargee()

- promote pargee() to a generic with methods
- add robust standard error
- re-work vignette
- add unit tests 
- add accessors for 'gdManager' (names may change)


git-svn-id: https://hedgehog.fhcrc.org/bioconductor/trunk/madman/Rpacks/geeni@89749 bc3139a8-67e5-0310-9ffc-ced21a209358
Merge branch 'local-hedgehog'