Provide support for translating java .properties files

Java applications use .properties files for translated strings instead of .po files.

It would be very nice to be able to import/export these files in Rosetta so that translation is possible through the fantastic web interface.

An example from messages.properties:

ChatAction.Help.me=/me <action> .............. Send an action

becomes

messages_de.properties

ChatAction.Help.me=/me <Aktion> .................. Sendet eine Aktion

Thanks for your time.