E2: Added E:constraintBreak(e)
Renamed E:constraintBreakAll() -> E:constraintBreak()
Fixed E:constraintBreak(s) always doing welds, oops
Hoverball rewrite

Rewrote from scratch to clean up code.
Fixed a problem where the strength option was ignored on spawn, and only
used on update or dupe (Thanks to Franc[e]sco for reporting this
problem)
Made glow sprite larger (it was there, but too small to see, before).
Renamed inputs/outputs, used the new alias feature to keep old dupe
compatibility.
Added Position and Distance output.
removed on state saving from thruster

There is no reason to save a thruster's on state because whatever you've
writed the thruster to will take care of that
Updated glow to match garry's

Glow becomes bigger the further away the hoverball is from its target
height
Clamped wire light's values, and added custom overlay

Fixes #684
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.