Fix for a Locale and error message comparison problem. My locale is German, and here different language strings were compared before.
Experimental localization plus in the CmdLineException
First localization offensive
Missing file added
Fix
Rename fixes also fix the problem with wrong default locale
Javadoc
Localize path error
Fix wrongly escaped Umlauts
Test case for localized CmdLineException
Different more elegant approach for explicitly accessing the English locale as a default in CmdLineException: Empty _en properties.
Renamed the files to match the ResourceBundle file lookup logic and fix a small bug.

The file Messages_de_DE.properties will ONLY be found for people speaking German and being in Germany. Austrians or Switzerland citizens also speak German,
but for them this file won't be found because of the ResourceBundle resolution logic.

The file name format for ResourceBundle property files can be:

     baseName + "_" + language + "_" + country

or
      baseName + "_" + language

(other options omitted)

The resolution algorithm is explained in the getBundle() Javadoc here:

	http://docs.oracle.com/javase/7/docs/api/java/util/ResourceBundle.html

The algorithm will start with the most specific locale matching file name variant and iteratively strip off parts.
It will never try other countries that seem 'friendly' or 'compatible'.

See this sentence for a clue:

 "If there are different resources for different countries, you can make specializations: for example, "MyResources_de_CH" contains objects for the German language (de) in Switzerland (CH). If you want to only modify some of the resources in the specialization, you can do so. "

This could be used for example country specific specialities which are probably not relevant for args4j.
Merge pull request #62

Conflicts:
	args4j/src/org/kohsuke/args4j/CmdLineParser.java
	args4j/src/org/kohsuke/args4j/spi/Messages.properties
	args4j/test/ExampleTest.java
restore the locale at the end
I think this name better reflect what it does
Merge pull request #66 from sfuhrm/localized-messages-fix

Renamed the files to match the ResourceBundle file lookup logic and fix ...
Merge pull request #67 from sfuhrm/code-cleanups

Code cleanups
CmdLineException separates message vs localized message now, so no need to mess with locales
Caching the default resource doesn't work well when we switch locales in tests
Compressed null pointer checks a little
More JavaDoc
Only static methods, so no instance allowed