[ft] FT_FloorFix and FT_CeilFix

[Wojciech Mamrak]

Hello,

FT_FloorFix does not round towards minus infinity and FT_CeilFix
towards plus infinity for fractional
negative values. This is inconsistent with expected semantics as well
as the docs, according to which these functions work as expected. The
problem with the docs is, that FT_RoundFix is semantically correct,
yet the description is incorrect w.r.t. to its semantics.
Werner pointed me out these are solitary (legacy?) functions not used
in FT anywhere, added back in 2001.

Example for FT_FloorFix: http://coliru.stacked-crooked.com/a/5f2b10846110c3d7

Please comment.