[ANN] opener 0.1.0 - open 'em all

Opener is a Ruby library for opening things in an cross-platform way.
It is a tiny (33 lines of code) alternative to the popular launchy gem.

## Version 0.1.0 (2013-05-07)

Minor:

  * Added Opener.exec() method for opening in-place!

Patch:

  * Opener.command() raises error if OS not supported.

Other:

  * Revised the Usage section of README a little bit. :slight_smile: