Adjusted the indentations of arrays.
* Added: the *redirect* field key for the submit input type that redirects the page after the submitted form data is successfully saved.
* Fixed: an issue that when there are multiple submit input fields and the same label was used with the *href* key, the last url was set to previous buttons; the previous buttons urls were overwritten by the last one.
* Fixed: a bug that a value for the *pre_field* was applied for the *post_field* key in some field types.
* Added: the ability to disable Settings API's admin notices to be automatically displayed after submitting a form by default. To enable the Settings API's notification messages, use the EnableSettingsAPIAdminNotice() method.