Replaces the default Silverstripe HTMLEditor (TinyMCE v3) with TinyMCE v4.

• HtmlEditorConfig is replaced with CustomHtmlEditorConfig
• HtmlEditorField is replaced with CustomHtmlEditorField

When using this module, beware: using HTMLEditorField will probably break the admin. Replace all occurences with CustomHTMLEditorField.

1. Using automatic scaffolding (scaffoldFormField):

	private static $db = array(
		'CustomContent' => 'CustomHTMLText'
	)

2. Using updateCMSFields or getCMSFields:

	public function getCMSFields() {
		$fields = parent::getCMSFields();

		$fields->insertAfter(
			CustomHTMLEditorField::create('CustomContent', 'Custom Content')->addExtraClass('stacked'),
			'Content'
		);

		return $fields;
	}

Note: Be sure to allow access to 'thirdparty/tinymce/tiny_mce_gzip.php'; a .htaccess file is added, some extra configuration is required when using Nginx.