Update copyright to 2013.
Merge branch 'master' into osx
Superficial change to PATH string.
Merge branch 'master' into osx
Adds MacPorts Python path and OS X user site directory.
Refactors the bash prompt.
Merge branch 'master' into osx
Bugfixes and tweaks to prompt.
Merge branch 'master' into osx
Adds pip download cache.
Merge pip download cache.