Cleaned up gate searching and categories

Searching:
* Removed search result slider (because it's no longer needed)
* Search box now tells you it's a search box
* Hitting enter after searching selects the top search result
* Cleaned up search list sliding animation code

Category tree:
* Left clicking a gate category now expands/collapses it (you no longer
need to click the tiny +/- icon)
* All gate categories will be loaded immediately instead of waiting for
you to open them.
* Removed "Gates" spam from category names. We already know it's a gate
category.
* Sorted categories alphabetically.