[truetype] Fix return values of GETINFO bytecode instruction.

* src/truetype/ttinterp.h (TT_ExecContextRec): New fields
`vertical_lcd' and `gray_cleartype'.

* src/truetype/ttgload.c (tt_loader_init): Initialize new fields.
Change `symmetrical smoothing' to TRUE, since FreeType produces
exactly this.

* src/truetype/ttinterp.c (Ins_GETINFO): Fix selector/return bit
values for symmetrical smoothing, namely 11/18.
Handle bits for vertical LCD subpixels (8/15) and Gray ClearType
(12/19).
4 files changed