v130704 Fixes

+ More checks for validity
+ Will now attempt to catch AJAX requests, and throw a WP_Error instead of redirect if caught to prevent problems with AJAX login widgets.
Various Changes to Upgrade to 130717

* Many filters and actions in the source code for advanced customization through PHP
* Various formatting changes in files
* Documentation changes
* Fixed an issue that would cause a warning in WP_DEBUG mode with non-AJAX logins
* Fixed an issue with redirects and sites running on HTTPS
* PHP includes now just reside in `/includes/` instead of `/includes/php/`