Langdisplay

This request implements an improvement in "multilanguage display" as is explained here:
http://pkp.sfu.ca/support/forum/viewtopic.php?f=9&t=13021

I'm sorry, but my development branch was a little bit dirty when I started.

Do you mind to forget the 5 first commits and cherry pick from:
"Config parameter to change galley display. Title not working yet" (9b02e7e)
till the end?

This pull request needs from lib/pkp changes to be complete.