nrsc - Take 2

After getting some good comments on nrsc and reading more. I re-wrote the implementation to append a zip file to the executable and serve resources from there (idea from Carlos Castillo).

The order you do the packing has change, you first "go build" and then run the nrsc script.

Here the nrsc script that packs the zip into the executable. The nrsc API didn't change that much.