New formula: lsusb

lsusb - List attached USB devices

`lsusb` is a Linux command that lists all devices currently attached to the USB bus. Mac OS X doesn't have this command, but provides the `system_profiler SPUSBDataType` utility. This formula installs a script that emulates Linux's `lsusb` behaviour, while providing similar functionality and syntax.

This version has been tested in Mac OS X 10.6-9, and should work in any Mac system that provides the `system_profiler` command.

**Updates from previous pull request [#23803](https://github.com/mxcl/homebrew/pull/23803):** Since the last pull request I received collaborations, made a couple of releases and improved the script.