Turned sim65 into a lightweight cc65 execution environment.

The sim65 source code has been a construction site for over a decade.
I was looking for a simple cc65 program execution environment for
regression tests. So I decided to re-purpose sim65 for that task by
removing about everything but the 6502 emulation.

There's no memory mapped i/o emulation whatsoever. Rather exit(),
open(), close(), read() and write() calls are supported by mapping
them through a thin paravirtualization layer to the corresponding
host os functions.

Note: The sim65 6502 emulation provides means to switch between
6502 and 65C02 emulation but currently there are no actual 65C02
opcodes implemented.

src/sim65/memory.h

@@ -38,20 +38,6 @@
 
 
 
-/*****************************************************************************/
-/*                                   Data                                    */
-/*****************************************************************************/
-
-
-
-/* Forwards */
-struct ChipInstance;
-
-/* Memory size of the CPU */
-extern unsigned MemSize;
-
-
-
 /*****************************************************************************/
 /*                                   Code                                    */
 /*****************************************************************************/
@@ -73,12 +59,6 @@ unsigned MemReadZPWord (unsigned char Addr);
  * overflow.
  */
 
-void MemAssignChip (const struct ChipInstance* CI, unsigned Addr, unsigned Range);
-/* Assign a chip instance to memory locations */
-
-const struct ChipInstance* MemGetChip (unsigned Addr);
-/* Get the chip that is located at the given address (may return NULL). */
-
 void MemInit (void);
 /* Initialize the memory subsystem */