[Vagrant] vagrant + puppet development box

This Vagrant box was tested with Max OSX and Ubuntu 12.04. 

I had some performance issues on my Ubuntu laptop, regarding to composer install - taking too much time and failing at the end, causing the other tasks (doctrine migrations, assetic etc) to fail since they depend on composer. But I was able to run it using 2048 mb memory on Vagrantfile and adding --prefer-dist to composer install.

This didn't happen on Mac OSX, though. It would be good if somebody else could test it before merge.

I also changed the app_dev.php to accept connections from private networks, so we can access the VM through the Host Machine.

Another thing is that I used git submodules to manage the puppet modules, but if you think its not a good idea for maintenance, I can change it to normal folders, the only negative point is that it may be harder to keep the submodules updated.

I'm going to write the Wiki page with detailed instructions.