Better error message for if you already have another server running

[scien]

events.js:71
throw arguments[1]; // Unhandled 'error' event
^
Error: listen EADDRINUSE
at errnoException (net.js:770:11)
at Server._listen2 (net.js:910:14)
at listen (net.js:937:10)
at Server.listen (net.js:986:5)
at Function.app.listen (/usr/local/lib/node_modules/lessthan3/node_modules/express/lib/application.js:534:24)
at runDevServer (/usr/local/lib/node_modules/lessthan3/bin/lt3.coffee:101:9)
at main (/usr/local/lib/node_modules/lessthan3/bin/lt3.coffee:146:16)
at Object. (/usr/local/lib/node_modules/lessthan3/bin/lt3.coffee:154:3)
at Object. (/usr/local/lib/node_modules/lessthan3/bin/lt3.coffee:156:4)
at Module._compile (module.js:449:26)
at Object.exports.run (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/coffee-script.js:83:25)
at compileScript (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/command.js:177:29)
at fs.stat.notSources.(anonymous function) (/usr/local/lib/node_modules/coffee-script/lib/coffee-script/command.js:152:18)
at fs.readFile