fix(project): only transpile aurelia_project in project root

closes #605

Author: JeroenVinke

lib/project.js

@@ -49,7 +49,7 @@ exports.Project = class {
   installTranspiler() {
     switch (this.model.transpiler.id) {
     case 'babel':
-      installBabel();
+      installBabel.call(this);
       break;
     case 'typescript':
       installTypeScript();
@@ -201,7 +201,10 @@ function installBabel() {
     plugins: [
       'transform-es2015-modules-commonjs'
     ],
-    only: /aurelia_project/
+    ignore: (filename) => {
+      let relativeFromProjectRoot = path.relative(this.directory, filename);
+      return !/^aurelia_project/.test(relativeFromProjectRoot);
+    }
   });
 }