Allow servers to run on two different ports.

As far as I can tell, there's no way to stop a server once you exit the
task that starts it.  Therefore, we have to run the two servers on
different ports to avoid conflicts.
Correct variable interpolation.
Fix bug in add_to_dist.
Put variables at the very top.

We want our variables values to be used even within the Bootstrap Sass
code.
Current conversion.  Very close.