fix(build): compile source files from within the src/ directory

We need to preserve the paths to be the same during build as they are in source repo,
so that editor and build pipeline are aligned.

Author: IgorMinar

lib/broccoli/angular2-app.js

@@ -57,10 +57,15 @@ Angular2App.prototype.toTree = function() {
       });
 
     // TODO(i): kill rootFilePaths in broccoli-typescript and use tsconfig.json#files instead
-    tsConfigCompilerOptions.rootFilePaths = tsConfigCompilerOptions.rootFilePaths.concat(tsconfig.files);
+    tsConfigCompilerOptions.rootFilePaths = tsConfigCompilerOptions.rootFilePaths.
+        concat(tsconfig.files.map(function(p) {
+          // TODO(i): this is a hack - for some reason we need to prefix all paths with srcDir because
+          //          tsc's "rootDir" doesn't take effect when resolving "files" paths
+          return path.join(sourceDir, p);
+        }));
 
 
-    var srcAndTypingsTree = mergeTrees([sourceDir, typingsTree]);
+    var srcAndTypingsTree = mergeTrees([sourceTree, typingsTree]);
 
     var tsTree = compileWithTypescript(srcAndTypingsTree, tsConfigCompilerOptions);