Hide all program output in HTTP server.
Hide all program output in HTTP server.

Previously, stderr of `make rebuild` wasn't redirected, meaning that
when uglify printed out a bunch of random newlines it littered the
console output.

Since it's pretty easy to tell when you've broken something in the
compilation process in dev, redirect even stderr in the server script.

reissbaker/gamekernel,reissbaker/gamekernel