debian package support for rbx 1.3

Files necessary to build a .deb package for Debian Stable(wheezy).

These files were prepared with a simple mechanical transform from the rbx 2.2 debian package files which are part of another pull request.

These build files expect patches on top of release 1.3.0 that were not included. The patches were submitted to be part of release 1.3.1

Rubinius 2.2.6+ or MRI 1.8/1.9 can be used to build the package.  Rbx1.3 was not tested.



Conflict & Replace MRI ruby packages.

gem is a separate alternatives command in rubygems1.8. This is broken. The gem
command is include in ruby1.9.1 package and in rubinius it is also included.
The gem command must switch in lock step with the ruby command otherwise
everything breaks.

I force package conflict until the MRI packages are fixed.