Version 0.1 - initial release (26 July 1994)

Version 0.1b (7 August 1994):

 * Various twiddles for Linux, HP-UX and IRIX platforms, including:
   - renamed getw and putw functions
   - redid initialisation of the sigaction structure not to depend on
     element order or on sa_mask being an integer
   - made requester ignore SIGALRM interruptions
   - changed srandom/random to srand/rand and inserted getwd definition for
     HP-UX.

Version 0.1c (7 November 1994):

 * Changed the undocumented instruction "sll" to fill with 1 instead
   of 0.
 * Slightly improved the R register emulation for a 4-5% speed increase
 * Made a few minor cosmetic changes to reduce compiler warnings
   slightly.

Version 0.1d (10 August 1995):

 * Fixed minor bugs in the sound output routine to improve the quality.
 * Improved sound synchronisation by not outputting data during periods
   of silence.
 * Fixed bug which makes border "bright white" on startup.
 * Fixed saver and loader so that they do precisely nothing when
   turned off.
 * Made multiload on by default.
 * Added support for LSBFirst displays, which previously caused a screen with each
   character squares mirrored.
 * Added kempston joystick emulation.
 * Modified X resource code to load app-defaults/Xz80 as well as ~/.Xdefaults.
 * Added Russell Marks's Linux console patch.
 * Added audio input.
 * Added TAP file support.
 * Fixed incorrect cycle counts on some of the LD r,n instructions, changed
   HALT to take a multiple of 4 cycles and revised estimates of number of
   cycles taken at interrupt.
 * Added "-border on|off|full" option with fancy borders.
 * Changed the default for -noprompt to be the same as -saver.
