[GRASS-translations] po files update

[Carlos Dávila]

Hello all translators
A long time has passed since last synchronisation of po files with 
current code, including Christmas break. I plan to update po files next 
Thursday 24th, so all translators are encouraged to send their files to 
svn or to me *before 17:00 GMT of Thursday 24*. Those how prefer to 
handle po files by themselves, please send me advise so I leave their 
language files unchanged.
Greetings
Carlos