==> add support for remote vmspace vmapbuf/vunmapbuf
==> add proper support for copyin/out_vmspace
==> add support for remote vmspace uvm_io
==> add support for non-curproc rumpuser_sp_copyin/out
==> store remote context in vm_map->pmap instead of
pthread_specificdata
In short, makes read/write of most (all?) block devices work from
a remote rump client via rump syscalls.
basics are there, but a few more tweaks are needed. The reason
I'm committing it now is that the code was mindnumbingly boring to
write (no wonder it took me almost 3 years to get it done), and I
might burn it if it's not in a safe place.
This incarnation is written in the user namespace as opposed to
the previous one which was done in kernel namespace. Also, rump
does all the handshaking now instead of excepting an application
to come up with the user namespace socket.
There's still a lot to do, including making code "a bit" more
robust, actually running different clients in a different process
inside the kernel and splitting the client side library from librump.
I'm committing this now so that I don't lose it, plus it generally
works as long as you don't use it in unexcepted ways: i've tested
ifconfig(8), route(8), envstat(8) and sysctl(8).
