Fix find expression for looking up .Rcheck

- use quoting
- limit depth
Merge pull request #126 from krlmlr/patch-1

Fix find expression for looking up .Rcheck
Bioc deps from package description.
Merge pull request #119 from siddharthab/master

Bioconductor dependencies from package description
Bioc devtools fix and indent
Merge pull request #130 from siddharthab/master

Bioc devtools fix and indent
Merge remote-tracking branch 'craigcitro/master' into install-build