v2.50

• DebugR fix: debugger assumed a 32-bit ring0 SS register on init;
  if this wasn't true, a crash may have occured.
• fix r cmd: the disassembler tried to show memory contents for the LEA
  instruction - this may have caused a GPF.
• DebugX fix e cmd, prompt mode: segment part changed to scratch sel
  after first line in protected-mode if it was a r/o selector.
• fix e cmd, prompt mode: '-' after byte input did skip that input.
• fix u cmd: address size prefix 67h for string instructions.
• fix n cmd: names > 128 chars may have modified debug's code seg.
• fix l & q cmd: failure of debuggee termination was ignored and the
  command continued, leaving an orphaned debuggee in memory.
• fix a cmd: regression since v1.18: "call/jmp [mem_ref]" without a size
  given did default to a far call/jmp.
• fix u cmd: operand size prefix 66h for 8/16/32-bit relative jmps.
• fix a cmd: NEar qualifier was accepted/ignored for immediate far
  jmp/call.
• u cmd, call far [mem]: qualifiers "FAR"/"DWORD FAR" changed to
  "FAR16"/"FAR32".
• DebugR(L): Q cmd may be activated for this variant.
• cmds bp/bc accept up to 4 permanent breakpoints.
• cmds bp/bc implemented, but inactive for Debug & DebugX; activated in
  DebugXg & DebugXv variants.
• G/T/P cmds: if possible, 386 debug registers will be used to set
  temporary breakpoints. Active for DebugX, DebugR(L).
• new cmdline options /s and /v for debugger variants that may use
  hardware breakpoints ( option /v not for DebugR(L) variant ).
• g cmd: if a breakpoint cannot be written, the cmd is aborted.
• Debug & DebugX may now be created in .exe file format.
• mktables.c: creates ASMTBL.INC/DISTBL.INC instead of DEBUGTBL.INC.
• cmds a, u: instruction RDTSC added.
• another variant of DebugR - DebugRV, with support for V86 mode.
• DebugR(V) dt cmd: optionally displays trapped ports.
• DebugRV di cmd: displays IDT & IVT vectors.
• DebugR rn cmd: won't run cmd if CR0.EM is set.