[BioRuby] Added Staden io_lib support for Ruby

[Pjotr Prins]

Hi,

For Ruby I have added support for reading and writing trace files,
using the Staden io_lib libraries (part of the Staden package). Now
you can easily parse those files:

See the API at

  http://thebird.nl/apidoc/biolib/index.html

I hope it is useful to someone.

Pj.