Fix error reporting when gatherImports failed

src/app/compiler.js

@@ -30,7 +30,8 @@ function Compiler (editor, queryParams, handleGithubCall, updateFiles) {
     files[utils.fileNameFromKey(editor.getCacheFile())] = input;
     gatherImports(files, missingInputs, function (input, error) {
       if (input === null) {
-        self.event.trigger('compilationFinished', [false, [error], files]);
+        self.lastCompilationResult = null;
+        self.event.trigger('compilationFinished', [false, { 'error': error }, files]);
       } else {
         var optimize = queryParams.get().optimize;
         compileJSON(input, optimize ? 1 : 0);