Ruby 1.9 support release.
### Improvements
* Supported ruby-1.9. [Patch by hallelujah]
* Supported $SAFE=1. [Patch by bon]
* Improved argument check. [Suggested by Morus Walter]
* Supported ruby-1.8.6 again. [Bug#27447] [Reported by Mamoru Tasaka]
### Fixes
* Fixed Ukrainan translation path. [Bug#28277] [Reported by Gunnar Wolf]
* Fixed a bug that only the last path in GETTEXT_PATH environment
variable is used. [Bug#28345] [Reported by Ivan Pirlik]
* Fixed a bug that Ruby-GetText-Package modifies $LOAD_PATH. [Bug#28094]
[Reported by Tatsuki Sugiura]