Make post_construct_and_drain_queue() not rely on destructor ordering as much. Also acquire an auto_drainer_t::lock_t earlier for safety.
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Check for missing .d files

Review 1151 by @srh
Fix build recipe for rethinkdb-gdb.py

Closes #1453
Review 1150 by @mlucy
Construct timestamp only when used in term_walker_t
Avoid copying of metadata in r.db() and r.table() (and a few others)
Merge branch 'daniel_read_optimizations' into next
Merge branch 'next' into sam_alt