General:
 - Joystick emulation with PC Joystick
 - improve man page
 - ? automatic frame rate / sound buffer size
 - show processor usage

Sound:
 - un-nice the program (optionally) to make sound better.
 - PC speaker sound

Screen:
  - better z80_mem -> image conversion 
  - on screen menus
  - ? monochrome displays
  - if memory problems while resizing do not exit
  - only update if necessary (border updatate cleanup)
  - Fix: bug if byte_order of client != byte_order of server

Z80 emulation:
 - implement all known undocumented instructions
 - optimize LD*R CP*R IN*R OT*R instructions

I/O emulation:
 - EVEN better timing for memory read/write (see aquaplane)
   
DOS Port:
 - sound support
 - ? use allegro's keyboard handling


Future plans (after version 1.0):
 - spectrum 128
 - AY8192 emulation
 - ? "mouse" joystick
