- new crange api
 - fix several crange bugs (see comments)
 - better scoped_acquire
compiles but still buggy and missing tlb shootdowns

fix shadowing declarations

"non-inline namespace cannot be reopened as inline"

use std::atomic, though with operator->() for now, since that can only be overriden with a member function

use atomic<> for dir pointer in an inode

crange and range "defined as a class here but previously declared as a
struct"

"non-inline namespace cannot be reopened as inline"