convert ::Import from pure Perl to XSUB
remove holes in switch for jumptables, assorted optimization cleanups

-no measurable speed change on benchmark.t, a little bit less instruction
 bytes tho
-move ApiFunction member, so the flags are byte ptr [reg], instead of reg+8
 or w/e
-T_NUMCHAR makes the in params more easily jumptableable on VC 2003,
 T_SHORT is the only hole now for in params, and that jumps to unknown
 type croak
-in param types are 1 lower than out params or the C constants, so 0
 means T_NUMBER and not T_VOID for in params only
convert Win32::API::Call from XS syntax to pure C

-this allows some unmeasurable in speed, but measurable in instruction
size optimizations by breaking up dXSVARS and mixing the misc extends
into the var declarations and initializations
pointerCall3Param optimization attempt