Changes in 2.6.8 (May 3, 2015):
- CPU / CPUDB
  - Bugfixes for CPU emulation correctness (critical bugfix for x86-64 emulation)
  - Memory type calculation support for Bochs debugger and instrumentation,
    to enable configure with --enable-memtype option.
  - CPUDB: Added Pentium (P54C) configuration to CPUDB
  - CPUDB: Added Broadwell ULT configuration to CPUDB
  - Updated definition of instrumentation callbacks, see description in
    instrumentation.txt / Fixed instrumentation examples
- Configure and compile
  - Configure option --enable-fast-function-calls now also used for MSVC nmake.
  - Some configure fixes for the GTK debugger support.
- GUI and display libraries
  - The VGA update timer mode now can be selected with the 'vga' option.
  - Release all pressed keys when the simwindow gets back the keyboard focus.
  - Win32 gui: Captured mouse cursor now really trapped in window.
  - SDL2: Implemented yes/no dialog (e.g. for VVFAT commit).
  - Some fixes for wxWidgets 3.0 and unicode version compatiblity.
  - Full save/restore support for enhanced gui debugger settings (window+font).
  - Added debugger support for the term gui using a pseudo-terminal.
- I/O Devices
  - Hard drive
    - Added Oracle(tm) VM VirtualBox image support (VDI version 1.1)
    - Re-enable "bulk I/O" repeat speedups extension.
    - Some lowlevel cdrom code fixes for Windows and Linux.
  - Sound
    - SB16: Fixed OPL chip detection by implementing ISA bus delay.
    - SB16: Ported OPL3 emulation from DOSBox and partly removed legacy code.
    - ES1370: Added MIDI UART output support.
    - ES1370: Fixed critical bug that made Win9x drivers crash.
    - Major rewrite of the lowlevel sound code.
      - Added mixer thread support (required for all modules except 'sdl').
      - New mixer and SDL mixer are polling data from the PCM output buffers,
        the PC speaker beep generator and the OPL3 FM generator.
      - PCM format conversion to 16 bit signed little endian.
      - Added sound 'file' module for VOC, WAV, MID and raw data output
        and added dual output support (device+file) in midi/wave mode 3.
      - Added capability to set up the sound driver per service.
  - Floppy
    - Fixed "Read ID" command for single-sided media (patch by Ben Lunt).
- ROM BIOS
  - Fixed keyboard scancode processing after keyboard intercept.
  - Fixed rombios32 code to avoid incorrect ACPI table detection.