Some fixes for the Tiny Core Image

Hi,

2 little patches to :
- Replace the sleep (for network) by a script which actually check the network (20 seconds was not enough in my case)
- Explicitly fetch the 1.3.4 version of the tilt gem because the one that was fetched by default (2.0.0) was breaking the sinatra gem.

The network check script will try to ping the foreman server (based on the kernel boot command line) every second for 3 minutes, perhaps not the better way to handle that (a better failure system if network is still down ?) but still better than the basic "sleep 20".

Regards,