DSPSpy: Unhide stack registers

The screen real-estate is already reserved, the values are dumped and
restored by the on-DSP code, why not make something out of these values ?
Allows following:
- where exactly send_back was called from ($st1)
- the boundaries and progress of the innermost BLOOP{,I} ($st0, 2 and 3)
  up to send_back's call

Source/DSPSpy/main_spy.cpp

@@ -149,13 +149,10 @@ void print_reg_block(int x, int y, int sel, const u16* regs, const u16* compare_
   {
     for (int i = 0; i < 8; i++)
     {
-      // Do not even display the loop stack registers.
       const int reg = j * 8 + i;
+      u8 color1 = regs[reg] == compare_regs[reg] ? CON_BRIGHT_WHITE : CON_BRIGHT_RED;
       CON_SetColor(sel == reg ? CON_BRIGHT_YELLOW : CON_GREEN);
       CON_Printf(x + j * 9, i + y, "%s ", reg_names[reg]);
-      if (j != 1 || i < 4)
-      {
-        u8 color1 = regs[reg] == compare_regs[reg] ? CON_BRIGHT_WHITE : CON_BRIGHT_RED;
       for (int k = 0; k < 4; k++)
       {
         if (sel == reg && k == small_cursor_x && ui_mode == UIM_EDIT_REG)
@@ -166,7 +163,6 @@ void print_reg_block(int x, int y, int sel, const u16* regs, const u16* compare_
       }
     }
   }
-  }
   CON_SetColor(CON_WHITE);
 
   CON_Printf(x + 2, y + 9, "ACC0: %02x %04x %04x", regs[DSP_REG_ACH0] & 0xff, regs[DSP_REG_ACM0],