Brand new minifiy hook... because there was errors left :/

Hi,

Sorry, I just realized today that there was a bug in CSSTidy, not corrected since 2007 as this project is dead and remains without any maintainer... my bad :/ This bug is particularly problematic as it breaks any media query, deleting parenthesis around them and so preventing them to be executed. I've just found out this after your last commit yesterday, with files.

I found YUICompressor which is a java program that can handle both CSS and JS files. So, I propose to use this one, which is working fine (as far as I tested it, I didn't found any problem with the minified files).

My proposition is to use this new YUICompressor. I provide a version of it in the .hooks dir, so anyone working on greeder just have to move the .hooks/pre-commit script to .git/hooks/pre-commit and it should work fine. Note that you must also install java first to run YUICompressor.

I took profit of this pull request to update the CSS and JS minified versions. Everything should be working fine and minified with this commit.