Thanks for the initial patch Claudiu - I tweaked it a bit before committing it.

* as you suggested, displaying the source is the default, with a --details option to display the formatted info instead
* changed the displayed details (e.g. only displaying the search path for packages, displaying the line number for classes and functions
* a few tweaks to the actual implementation (e.g. using partition over find, avoiding tracebacks for a couple of likely user errors)