v0.72: Extended memory support for Apple //e

- Implemented initial version of extended memory support, which allows the EightBall source code to be stored in aux RAM (extended 80 column card).  Once an apparent bug in the cc65 extended memory driver is fixed then bytecode will also be stored in aux RAM.
- Moved non-performance critical portions of interpreter / compiler to Apple II language card memory, which frees up more main memory.
- Improvements to display of free memory (`free` command)

disass.c

@@ -284,5 +284,8 @@ int main()
     printchar(147);             /* Clear */
 #endif
     disassemble();
+#ifdef A2E
+    cgetc();
+#endif
     return 0;
 }

eightballutils.h

@@ -37,7 +37,7 @@
 /*                                                                        */
 /**************************************************************************/
 
-#define VERSIONSTR "0.71"
+#define VERSIONSTR "0.72"
 
 void print(char *str);
 

err.8b

@@ -0,0 +1,28 @@
+word counter=0
+word fails=0
+
+call expect(sqr(10)==100)
+end
+
+sub sqr(word x)
+  return x*x
+endsub
+
+sub expect(byte b)
+  pr.dec counter
+  pr.msg ": "
+  counter=counter+1
+  if b
+     pr.msg "  Pass "
+  else
+     pr.msg "  FAIL "
+     fails=fails+1
+  endif
+  pr.nl
+  return 0
+endsub
+
+sub xxxxxx(word qqq)
+ return qqq
+endsub
+