decide which mirror to choose locally and display result

closes #3904
Fix TechTree prerequisite bug for buildings with a build limit.

Fixes where a building/unit whose prereq is a build limited structure
was always available to be built even when the prereq was not satisfied.
Rewrite for better efficiency

uses a single, more concise statement rather than an if statement, and
checks buildLimit before attempting to check if the buildables cache
contains the key.
add Tiberian Sun refinery
add Tiberium to Tiberian Sun
Remove an outdated hack from Renderer.
Reference mono's libfreetype under osx.
remappable resource types
Make TeslaZap color palette customizable.
Make MuzzleFlash palette customizable.
Move winforms crash dialog into an external helper.
Add a native crash dialog for OSX.
Remove Windows.Forms dependencies from game and utility. Fixes #4348.
tweak: artillery min. range slight increase

Artillery was recently buffed, but I think this makes the fact that they can currently fire at close range is not appropriate. I think artillery should be vulnerable to units that are able to get quite close, instead of being able to fire at them and do massive damage.

The reason min. range of 2c896 was picked is that when you set min. range to 3c0, it is not able to fire exactly 3 cells away. Perhaps the behaviour should change so that 3c0 = 3 cells away. 

(For comparison, MLRS has minimum range of 3).
Merge pull request #5238 from reaperrr/more-palettes02

More palette un-hardcoding
Merge pull request #5244 from pchote/bye-bye-winforms

Remove X11 dependency from OSX.
Closes #3872
Closes #4348
Slight buff HeliGun vs. light

Apache, for all its greatness, doesn't do very well at one of the things it's supposed to do well, namely take out light vehicles quickly (humvee, artillery, MLRS, etc.). Apache is required for Nod as a reliable way to take out MLRS, but currently it doesn't do enough damage to take it out with its entire payload (which takes 4 seconds to unload, to boot). A single Apache should be able to destroy an MLRS, if it gets the chance.

If anyone thinks the Apache needs nerfing, I would suggest looking in other areas besides its damage vs. light armor. 

Also, does anyone object to removing the AG/AA distinctions for helicopters? They don't seem needed anymore.
fixing some trees

A couple of trees have a footprint that is too big. It looks like you should be able to drive by them, but you can't. They have been set overly-large.
fixing tree cluster

This tree cluster looks like it should be passable through in this cell. Looks fine in testing, even though looked like it might be wrong in map editor.
closes #3091 Have Helis take off after repair/rearm