Proposal for issue #972

Hi,

I made some changes in the linux build process. The goal was to make it independent from an older compiled version of LightTable. It allows to choose the node-webkit version and thus will solve the issue number #972. As I'm not sure about how the whole build process works, I may have forgotten some key points, so please let me know if I can improve anything.

Here are more details about the modifications I made :
- Don't download pre-compiled version of LightTable. Instead :
- Download node-webkit binaries and copy files into "deploy" directory,
- Create a "resources/default-plugins.tar.gz" file containing default plugins (copied from http://d35ac8ww5dfjyg.cloudfront.net/playground/bins/0.6.0/LightTableLinux64.tar.gz )
- Change binary version in "version.json" file.

I successfully tested this corrections on both Debian Linux Wheezy 32 and 64bit. Hope it can help to fix issue #972.

Any comment welcome !