Stage default file loading

This is my documentation of solving a bug related to loading a default file on the stage.

When we open a project folder, the following checks happen to load the stage with an HTML content.

1. Check if the project root directory has an index.html file and load it.
2. If no index.html file present, then load the next available ".html" file in the directory which comes at top in ascending order alphabetically.
3. Now, what if their are no files present in the root directory of the project. In that case we create a index.html file and fill it with some dummy html.

And the current issue #621 that I'm solving is related to that.