fix brackets
add comments; move version output

+ Added and expanded comments to make it more obvious as to what is happening
* Made it so that both successful and unsuccessful requests output the API
  version; previously only unsuccessful requests did so
+ Bumped API version
Changed error message on non-POST request

Changed the error message 2, which is displayed when a user attempts to send a
non-POST request to `upload.php` to display the request type, in an attempt to
make it easier to troubleshoot.

Bumped API version.