Update zdefs.acs with shadow and subtract styles. 

I'm not sure why the values jump from 1, 2, 3, 4, 5 to 64, 65, 66, 67, but I continued from there. Adding shadow is necessary to add subtract.
- ChangeActorAngle/Pitch added to zspecial.acs.
- new render styles.
Fix compilation on OS X and other systems without non-standard <malloc.h>

All required declarations are in <stdlib.h>
Don't convert string constants to numbers for #define

- Fixed: You could not #define a string for use in a library, because it
  was converted to a number at definition time and not at use time. This
  is no longer the case. Symbolic constants now store the string in its
  original form, and they now expand into the string when encountered
  instead of their string table index.
Fixed: One use of ERR_NOT_AN_ARRAY did not provide the symbol's name
Add script/function arrays to ACC

- Script arrays are semantically identical to map arrays: They have fixed
  sizes and can be multidimensional. They can also be initialized, although
  this is just syntactic sugar. e.g.
    int init_array[2] = { 10, 20 }
  produces code identical to:
    int init_array[2];
    init_array[0] = 10;
    init_array[1] = 20;
  Script arrays are also implicitly initialized to 0, just like any other
  variable in ACS.
- Unlike map arrays, they only exist for the life of the script, and each
  script gets its own copy of the array.
- Script arrays exists in a separate space from script variables. I did
  not repeat the bullshittery of map arrays here. (I still have no idea what I
  was thinking when I designed them that way.)
- Each script and function that uses local arrays is recorded with a new
  chunk: SARY for scripts and FARY for functions. The first two bytes are the
  script/function number, and the rest of the chunk consists of four-byte
  integers describing the size (in ints) of each array used by that
  script/function. To determine how many arrays a script/function uses,
  take the chunk length, subtract two, and divide by four.
Improve error message when using functions in Hexen-compat mode

- When trying to define a function with the -h switch, you previously
  got two error messages on the token following the function, making it
  unclear what the problem was. There is now only one error message at the
  end of the function's parameter list.
Remove dead "language" code from ACC

- This is a feature that never saw the light of day in this form, so get
  rid of its vestigial remnants. (Note that this is NOT the l: print
  formatter that causes the game to look up a string in the LANGUAGE
  lump.)
Add PCD_GOTOSTACK

- It's not used. It's just there as a placeholder.
Fixed: scriptarray[i] += x generated &= x instead
- BlueShadow's GetArmorInfo submission.
Merge branch 'master' of https://github.com/rheit/acc
- new armor info type.
Ceiling_CrushAndRaiseSilentDist
- Include with DropInventory with Blue Shadow's patch.
Merge branch 'master' of https://github.com/MajorCooke/acc
Add PickActor function
Add actor flags for PickActor.
Add linedef flags for PickActor.