[GSoC Weekly Status #3] bhyve debug server enhancements

Hello,

I've spent the last week implementing hardware watchpoint support for
bhyve's gdb stub. Aside from adding minimal kernel-side support for
forwarding relevant VMEXITs to userland, most of the changes revolved
around tracking the state of the guest's DR* registers and placing gdb's
watchpoints in available registers. I'm happy to report that the basic
functionality is working properly and that the feature will be thoroughly
tested during the next week.

Bojan