Allow application of the unary ! operator to floating constants.

The following is an example of a program that requires this:

#include <stdio.h>
int main(void)
{
    int true = !0.0;
    int false = !1.1;
    printf("%i %i\n", true, false);
}

Expression.pas

@@ -1341,6 +1341,11 @@ var
                      op^.token.kind := doubleConst;
                      op^.token.rval := -rop1;
                      end;
+                  excch       : begin                        {!}
+                     op^.token.class := intConstant;
+                     op^.token.kind := intconst;
+                     op^.token.ival := ord(rop1 = 0.0);
+                     end;
                   otherwise   : begin                        {illegal operation}
                      Error(66);
                      op^.token.class := doubleConstant;