Adding sample for Coffeescript too

lib/linguist/languages.yml

@@ -569,6 +569,7 @@ CoffeeScript:
   extensions:
   - .coffee
   - ._coffee
+  - .cake
   - .cjsx
   - .cson
   - .iced

samples/CoffeeScript/build.cake

@@ -0,0 +1,17 @@
+fs = require 'fs'
+
+{print} = require 'sys'
+{spawn} = require 'child_process'
+
+build = (callback) ->
+	coffee = spawn 'coffee', ['-c', '-o', '.', '.']
+	coffee.stderr.on 'data', (data) ->
+		process.stderr.write data.toString()
+	coffee.stdout.on 'data', (data) ->
+		print data.toString()
+	coffee.on 'exit', (code) ->
+		callback?() if code is 0
+
+task 'build', 'Build from source',  ->
+	build() 
+