Push ftruncate operations down through the diskmgr into the i/o pool.
Fixes a problem with conflict detection in the case of multiple resize operations being queued/active at the same time.
Merge branch 'next' into daniel_265
Merge branch 'next' into daniel_265
Changed resize conflict-resolution logic. I think it's more robust now.
Wrote unit tests for resizing conflict resolution.
Fix oversights after refactoring.
Made eviction_bag_t use hypothetical_memory_usage instead of something else.
Front-loaded page-is-loading accounting.
Made page_t::is_loading be correct with the new semantics.
Merge branch 'next' into daniel_265
Merge branch 'sam_2100' into next
Make i/o account destruction wait for all requests to finish.
Stylistic fixes and such.
Very minor stylistic thing
Revert accidential change.
Merge branch 'next' into daniel_265
Simplified resize unblock logic.
Un-added a static_cast.
Lazily construct auto_drainer_t in disk mgr accounts.