UI Update - Graphical and code changes

Changed player_updateGui.sqf with an update to how the UI elements are
loaded. Changed all status icons to use the full value so no more fading
icons. Also changed the colors from red/green setup to a black and white
setup. All icons start off as black if the value is optimal, (full
blood, full food/drink, temperature, out of combat, seen, heard), then
progress continually towards white as the player loses blood, gets
hungry, etc. This was done to make the differences between full and
empty more drastic as the current method starts off with obvious icons
that slowly fade. If player is color blind, there have been reported
issues of the two colors showing up as similar shades of gray. For those
that are not CB the elements currently become less obvious in the user's
peripheral until they begin flashing. Changes also made to variables.sqf
to add the ability to turn this feature on/off:
Dayz_Dark_UI = true;
Sets UI to new darker theme. Turned off by setting the value to false.
Merge pull request #1384 from hogscraper/test_branch

UI Update - Graphical and code changes