Merge branch 'next'

* next:
  minor, separate guts that actually call engine code, into rotz-tcbdb and rotz-lmdb
  hygiene, spell file name properly in header
  chore, actually use the USE_LMDB conditional to guard the build of the rotz-dump tool
  chore, provide USE_*DB automake conditionals
  hygiene, don't fiddle with generated c from ggo code more than necessary
  chore, move auxiliary build files into build-aux/
  minor, import basic test harness
  Revert "chore, tentative, set db size to 512MB max in lmdb mode"
  chore, tentative, set db size to 512MB max in lmdb mode
  minor, provide simple dumper for rotz lmdb files
  chore, use predefined RTZ_VTXKEY_Z and RTZ_EDGKEY_Z instead of recomputing it
  hygiene, use mdb_dbi_close() not the kludge that clashes with libmdb
  chore, strike tokyocabinet CFLAGS and LIBS from rotz-search specs
  Revert "test, just use one big transaction over the whole lifetime of a rotz_t context"
  test, just use one big transaction over the whole lifetime of a rotz_t context
  fix, PEBKAC, typo, allow lmdb in --with-database
  fix, PEBKAC, define a version of struct rotz_s for rotz-fsck