Save file contents periodically

And don't rely on the auto-compile feature to do so.

src/app.js

@@ -455,10 +455,13 @@ var run = function () {
 
   function editorOnChange () {
     var input = editor.getValue()
+    // save contents
+    editor.setCacheFileContent(input)
+
     if (input === '') {
-      editor.setCacheFileContent('')
       return
     }
+
     if (input === previousInput) {
       return
     }

src/app/compiler.js

@@ -41,7 +41,6 @@ function Compiler (editor, handleGithubCall) {
     editor.clearAnnotations()
     self.event.trigger('compilationStarted', [])
     var input = editor.getValue()
-    editor.setCacheFileContent(input)
 
     var files = {}
     files[utils.fileNameFromKey(editor.getCacheFile())] = input