Release Name: 1.5.5

Notes:
* Now compatible with Ruby 1.9.x
* License changed to Artistic 2.0


Changes:
* Now compatible with Ruby 1.9.x.
* License changed to Artistic 2.0.
* Added test-unit 2.x as a development dependency.
* Test suite refactored to take advantage of some of the features of
  test-unit 2.x, as well as fixes (skips) for BSD platforms.
* Several gemspec updates, including the license and description.
* Renamed test file to test_proc_wait3.rb.
* Example files renamed to avoid any confusion with actual test files.
* Several Rake tasks added to run individual example programs.