Add somagic and somagic-tools formulae

Adding two formulae for [easycap-somagic-linux](http://code.google.com/p/easycap-somagic-linux), a linux userspace driver for Somagic EasyCAP devices.

`somagic` has `somagic-tools` as a required dependency since an initial run to extract the firmware file from the vendor CD is required, before running an actual capture session. `mplayer` is an optional dependency for easy piping of capture output (examples are given in `--help`)

Both firmware extraction and capture have been tested and work on my setup (OS X 10.8.4).