fix expressionDependencies on expression


 - The value from recursive calls should be returned
 - `fileDependencies` always call `expressionDependencies` with language or symbols instead of            expression, so this chunk is never used and can be safely removed for now.
Merge pull request #44 from luckyrandom/patch-1

fix expressionDependencies on expression
Merge pull request #45 from krlmlr/bootstrap

Streamline bootstrapping
Strip whitespace; update .Rproj settings; re-roxygenize
Import pkgVignettes from tools
Only re-set CYGWIN if it's already set
Minor tweak in messaging
In interactive sessions, let the user know they're in a packrat project
Load dependencies from files ending in .r (#48)
Update status to return more information to the user
Search for .R, .Rmd, .Rnw, .Rpres deps
Display packrat sources as well
Have readLockFile attach name to list returned
Make sure we correctly find the packrat sources
Improve the status printout
Make sure library printed first
Bump version
readLockFile handles multiple repos
Merge branch 'feature/new-status'
Better dependency handling