"Jump to new item" not very intuitive

[matt]

On various places where we do AJAX adding, like the users page, instead of saying something like we used to, such as "New user added" we now say "Jump to new item". We should try to make this friendly.

Also, error messages and other messages should go *above* the form, not below it.

[mdawaffe]

better messages, markup validation

[mdawaffe]

"User X added"

"Category X added"

Validate the markup on users.php and categories.php.

Put messages above form.

Will need to bump two JS versions in script-loader.php.

[ryan]

(In [4583]) Better AJAX feedback messages and markup fixes. Props mdawaffe. fixes #3208