GXemul Code2

Nicer release notes.

Adding detection of /opt/X11/{include,lib} in the configure script, to build with X11 on MacOS with XQuartz installed (thanks to eschatologist in the #GXemul IRC channel on FreeNode for noticing this).

Removing guestoses.html.

Moving remaining modes from unsupported.html into individual machine pages, so that unsupported.html can be removed.

Removing the SGI IP30 and IP32 modes from the new framework; SGI machines are emulated using the old framework.

The guestoses.html page is almost gone.

Removing the QEMU_MIPS machine mode, which was useful back in 2006 to compare performance against QEMU's MIPS emulation.

Adding machine_evbmips documentation.

Adding machine_prep documentation.

Adding machine_pmppc documentation.