Support for recent AAE index

With basic ct test.

Doesn't currently prove expiry of index.  Doesn't prove ability to find
segments.

Assumes that either "all" buckets or a special list of buckets require
indexing this way.  Will lead to unexpected results if the same bucket
name is used across different Tags.

The format of the index has been chosen so that hopeully standard index
features can be used (e.g. return_terms).

include/leveled.hrl

@@ -5,8 +5,6 @@
 -define(STD_TAG, o).
 %% Tag used for secondary index keys
 -define(IDX_TAG, i).
-%% Tag used for near real-time anti-entropy index keys
--define(AAE_TAG, i_aae).
 
 %% Inker key type used for 'normal' objects
 -define(INKT_STND, stnd).