New Expanded Memory control parameters. I also took existing (unused) code to allow starting the DOS VM in virtual 8086 mode and extended it to do basic virtualization. Some VCPI fixes, some EMS fixes, and XMS fixes. A particular demo on scene.org I found would not run without both expanded memory and virtual 8086 mode, which is why I added the virtual 8086 mode setting.
Known problems at this time: the virtual 8086 mode works perfectly fine with DOS programs. However for some odd reason Windows 3.1 and most DOS extenders complain about insufficient XMS memory (despite that MOST of it is free). Some other DOS extenders such as Microsoft DOSXNT and DOS32/a cause DOSBox-X to segfault or cause erratic crashes.
Also merged into this build are mainline DOSBox SVN commits from October 2014 to January 2015.