New features:
- add support for BRIN indexes (for pg 9.5+ obviously).
- handle index on predicate.
- handle index storage parameters for supported index methods. For now, this means :
- fillfactor for btree indexes
- pages_per_range for brin indexes
Bug fixes or improvements:
- check that number of column is suitable for a real index
- free memory when hypothetical index creation fails
- for btree indexes, check that the estimated average row size is small enough to allow a real index creation.
- safer handling of locks.
Misc:
- remove the simplified "hypopg_add_index()" function