Allow define RUBY_CONFIGURE_OPTS on rbx configure

The configure of rbx can take a RUBY_CONFIGURE_OPTS. You can by example
use the `--skip-prebuilt` OPTS
Merge pull request #354 from shingara/features/configure_on_rbx

Allow define RUBY_CONFIGURE_OPTS on rbx configure
Add a definition for Ruby 1.9.1-p430
Add a definition for Ruby 1.9.2-p0
added 1.9.3-p426 and 2.0.0-p195
Merge pull request #356 from hsbt/added-latest-releases

added 1.9.3-p426 and 2.0.0-p195
Replacing 1.9.3-p426 with 1.9.3-p429

1.9.3-p426 was deprecated by 1.9.3-p429 since it won't build on RHEL6
systems (and others?)
Merge pull request #359 from artificialrobot/master

Replaced 1.9.3-p426 with 1.9.3-p429 definition (p426 was yanked after release due to build issues)