update po file from transifex

It add a dependency : 
apt-get install transifex-client

after to update just run in root package folder 
tx pull -a

it's also possible to update transiflex auto from a pot file on github, but will look at this later

also you nee to create a file (~/.transifexrc), like explain here 
http://docs.transifex.com/developer/client/setup#transifexrc

i will send by mail mine, as i don't find yet hot to create a xbian user as admin in transifex

are you ok with this solution?