Added the english source file based on fr.php

I've create the file based on fr.php and doing a simple transform in vim with a regular expression

    :%s/\(".*"\) => \(".*"\)/\1 => \1/g


After this I uploaded the file to transifex and created a project for easy translation [here](https://www.transifex.com/projects/p/owncloud-polls/), I used that for my catalan translation. If you like I can transfer the ownership (I just use transifex because it's really easy)