[ft] Subpixel Hinting Patch

[Moony]

http://www.infinality.net/files/subpixel-hinting-20100416-4.patch

Here is the latest version of the subpixel hinting patch.  This one is 
intended to be more "cleaned-up" than the older ones.  It is an 
all-in-one patch that should cleanly patch freetype-2.3.12, enable LCD 
filtering, subpixel rendering, and the new subpixel hinting.

Notable differences with this version compared to previous versions:
* Much, much cleaner.  Removed the global variables and did proper 
indenting.  ;)  Could still be optimized more however.
* Preserves bi-level hinting when bi-level is requested, and enables 
subpixel hinting when "grayscale" is requested.
* Should perform similarly to plain freetype bi-level TT hinting. 
(although I have not done actual comparisons)
* Follows the whitepaper ( 
http://www.microsoft.com/typography/cleartype/truetypecleartype.aspx ) 
more closely, modifying the rounding functions instead of the moving 
functions.
* No longer crashes OO.org or any other program that I'm aware of!

Please feel free to make suggestions and criticisms of the approach and 
implementation.  My goal is to make this patch quality and accurate, and 
get it into the freetype tree if possible.  There are plenty of 
improvements that can still be made, in features and implementation.