Reverted changes for Spartan3E compile

Hi Jac,
I decided to revert the changes I made to the code to make it compile using the old Spartan3 compiler in ISE since there is very little benefit doing this and it still has issues with $readmemh.  The reverted code now only has changes from the original Parallax release that's absolutely needed in order for it to compile on Spartan6.

Magnus