tweak viewports

skip experimental 6th viewport that got forgotten
and limit max zoom to 7 (range 0-7) which is what looks good

mandel.s

@@ -296,7 +296,6 @@ viewport_zoom:
     .byte 7
     .byte 5
     .byte 7
-    .byte 8
 
 viewport_ox:
     .dword ($00000000 & $3fffffff) << 2
@@ -1393,7 +1392,7 @@ skip_char:
 
 plus:
     lda zoom
-    cmp #8
+    cmp #7
     bpl skip_char
     inc zoom
     jmp done
@@ -1427,8 +1426,6 @@ number_keys:
     beq four
     cpy #KEY_5
     beq five
-    cpy #KEY_6
-    beq six
     jmp skip_char
 
 one:
@@ -1445,9 +1442,6 @@ four:
     jmp load_key_viewport
 five:
     ldx #4
-    jmp load_key_viewport
-six:
-    ldx #5
     ; fall through
 load_key_viewport:
     jsr load_viewport