Add Travis CI configuration.
Only test 1.9.3 because we only support this one now.
MultipleOfValidator delegates to DivisibleByValidator.

This fix a design defect since a multiplier is not a divider
obviously...
Fix listing in release notes.
Use debugger 1.6.0.

This version is compatible with both 1.9.3-p448 and 2.0.0-p247.
Change assert_match parameters order.

This way we please both ruby 1.9 test framework and mini test for
ruby 2.0.

Thanks to Chi-Ting Leung <chiting.leung@gmail.com>
Merge branch 'topic/ruby-2-compat'

* topic/ruby-2-compat:
  Change assert_match parameters order.
  Use debugger 1.6.0.
Enable ruby 2.0.0 for CI.