accessors for:
* struct mount & VFS ops
* struct uio
* struct vnode
* struct vattr
and some namespace games for:
* namei flags
* VOPs
* enum vtype
Also, split rump services into two categories: library private and public
(rump_private.h and rump.h, respectively).
As a result, it is now possible to compile and use the NetBSD kernel
file systems on Linux (and probably other systems too with very
little work), although the makefiles need a bit of work to make it
a pleasureable experience.