Internationalization: set default language

[Francesco Malvezzi]

> hi everybody,
> 
> [...]
> 
> What did I overlook?

I overlooked to describe what's inside $IDP_HOME/messages.

$ ls messages
messages_en.properties  messages_it.properties  messages.properties

where 'messages.properties' has only the 'idp.log' and the css thing 
that are common between the languages.

messages_en.properties and messages_it.properties contain the overrides 
from the system's translation, few lines each when a customization was 
needed,

thank you,

Francesco