lighttpd not built/installed by default

[fivebats]

The default build in external/Makefile doesn't make or install lighttpd. Is that intentional, or should it perhaps be added to the LIBS = in the Makefile?

If lighttpd is not installed the launch-webserver script will not work properly.

[ViralBShah]

It was intentional, because the web repl is quite new. It has matured a fair bit and now that we even have the preliminary graphics capabilities, I guess we can make lighttpd part of the default build. Let's see what others have to say, and then decide if it should be in default build or not.

[Keno]

I think it would be a good idea to at least give some sort of warning when trying to use launch_webserver (à la "lighttp is not installed run command to install). That way people don't get confused why it's not working even if it's not default.