Cleaner implementation of expressionDependencies
Fix bug: after initial bootstrapping, library path is searched for dependencies
Remove .Rprofile from gitignore
Fix bug: superfluous warning on initial bootstrap
Support lockfile generation for packages not installed locally
Implement status()
Merge remote-tracking branch 'jcheng5/diff'

Conflicts:
	R/pkg.R
README tweaks
Deal with RC methods
Merge pull request #1 from rstudio/exprdep

Cleaner implementation of expressionDependencies
Clean up output and improve robustness during source package download and installation
Add option to specify local source package locations for packing
Initial implementation of addPackages
More accurate detection of bootstrapping of package
Fix broken lockInfo calls
Implement add(). Pretty sure this is wrong.
Initial support for Bioconducter packages and repos
Version format for Packrat DESCRIPTION file
Add GitHub annotations in DESCRIPTION files for source pkgs
Add \n to end of DESCRIPTION file before appending

write.dcf isn't smart enough to add a newline to the end of a file
that doesn't have one already. This can cause the collate field (or
whatever field comes last) to break.