new API FT_Get_Gasp to return entries of the GASP table
        corresponding to a given character pixel size.

        * src/sfnt/ttload.c: add version check for the GASP table,
        in order to be better future-proof

        * include/freetype/config/ftheader.h: add definition of
        FT_GASP_H, corresponding to <freetype/ftgasp.h>

        * src/base/rules.mk, src/base/Jamfile, modules.cfg,
        builds/win32/visualc/freetype.dsp,
        builds/win32/visualc/freetype.vcproj: Adding src/base/ftgasp.c
        to the default build