amberc.js: export AmberC constructor as exports.Compiler

bin/amberc

@@ -1,4 +1,6 @@
 #!/usr/bin/env node
 
 var amberc = require('./amberc.js');
-amberc.main();
+
+var compiler = new amberc.Compiler();
+compiler.main();

bin/amberc.js

@@ -740,4 +740,4 @@ AmberC.prototype.closure_compile = function(sourceFile, minifiedFile, callback)
 	);
 };
 
-module.exports = new AmberC();
+module.exports.Compiler = AmberC;