This commit adds a `Future` scope to the configuration options, and for
the time being includes a single flag within that scope: `rename`.
Usage:
--future.rename
The value is a boolean available internally at: m.Config.Future.Rename
It's not enough to back up each index's translation keys after
backing up that index's data; we also have to back them up after
backing up any index data from indexes which have foreign key
references to that index. So we do the per-index passes separately.
Since the individual backup data files are being created separately,
the expected output is unchanged for a quiescent database, the only
difference is that the amount of translation info which might be
newer than the data stored for shards is potentially increased.
Previously the backup tool only fsync'ed the files.
Since the directories were not synced, it was possible for the references to be lost.
Now we sync the entire output directory tree and its parent.
Attributes are unmaintained and unused.
They have become more of a liability than a benefit.
This change eliminates them from the codebase.
The only user-visible change (assuming that attrs are not used) is that the attrs field will no longer appear in row JSON.
When unmarshalling ops, we weren't adding a meaningful OpN to them,
resulting in misleading reports from `pilosa inspect`. Also, we were
mistakenly reporting things as "mapped" when they were actually
using their internal storage (as with small array containers).
Add the "sanity check" to `pilosa inspect` so that errors like the
above get noticed more easily and corrected. Also, to make that work,
have roaring.InspectBinary actually put containers in the bitmap
it creates rather than just creating info entries for them.
