This drops support for the pre-challenge-response authentication scheme
(i.e. the scheme in use before Zarel/Pokemon-Showdown@7dbd8cfec5 on
February 8, 2013), and, by doing so, simplifies quite a bit of the
authentication code.
In particular, it is no longer necessary to make any database queries in
index.php, which reduces our database use significantly and also moves us
closer to the goal of the index page being static HTML.
Previously, a bug prevented a replay from being re-uploaded if the
first replay upload failed, or if the battle continued after a
replay was uploaded. This has been fixed.
The replay upload system should be a lot less brittle now. Errors
should be rarer, and when they do happen, the error message will
be clearer.
For instance, 'hash mismatch' will happen much less often, and
when it does happen it will give the message: "Someone else is already
uploading a replay. Try again in five seconds."
This moves most of the logic of action.php into a separate file
lib/dispatcher.lib.php and separates the actions into ladder-related
actions and non-ladder-related actions. This is intended to make it
possible to have a second action.php that handlers only ladder-related
actions, which can run on the main server computer and allow
that computer to make HTTP requests to `localhost`, which should
help reduce ladder errors.
