Fix FDCT to be 16-bit and ANSI compliant.

	* src/fdct/fdct.c: Use ANSI style comments and 80 column
	throughout.  Correct expected value for block[12].  Add GPL header.
	(void fdct): Use long int instead of int for all temporaries.
	(int main): Use long int where needed.  Add check blocks for 1 and
	4096 transformations and use where appropriate.