Icon fix on OSX 10.8 and other improvements

[mgibeau]

The icon was not loading on OSX 10.8, not quite sure why, but a combination of the file:// protocol and a check for localhost in ruby_gntp breaks it (see: snaka/ruby_gntp@e84809d). It's a bit of a hack but I was able to avoid this by instantiating GNTP using 127.0.0.1.

While at it I made a few improvements:

• Proper application name
• Better title, this also allows for more characters to be shown on errors
• Sticky for errors (inspired by the compass doc)
• New icon :)
• Finally, there was an error with the constant used for the init, it's fixed