Update index.php
Update index.php

- Removed old version update support compatibility.
- A better definition of public/private functions.
- Corrected code logic in theme/plugin installer with an array check.
- Added hash_equals checks to prevent CSRF timing attacks.
- Added link to WonderCMS homepage in the Settings panel.
- Minor text changes to the Settings panel and error messages.
- Minor Settings panel design changes.
- Prettified code fixes.
- CSS fix, removed bottom border on the settings panel links. The border was visible only when designing a new theme/template from scratch.
- Functions re-sorted alphabetically for easier overview.
- Added 404 page editing support.
- Added whitelist for allowed file type uploads.
- Restructured function for deleting files, themes and plugins.
- Updated taboverride and autosize to latest version.
robiso/wondercms