Move staging to BUILD copy logic from template to library
Add reference to README.md about Mac OS X packages

Seems silly to have such a useful feature and not advertise it!
Merge pull request #553 from fatlotus/patch-1

Add reference to README.md about Mac OS X packages
Merge branch 'master' of github.com:jordansissel/fpm
- abort if a user tries to package up the temporary directory (#542).