It builds!
Get an implementation of haystack indexes compiling, rename
indexDetailsBase to IndexInterface
Add missing files for haystack
Get started on 2d, which is a complete disaster
Adding 2d index files
Disable 2d for now
Rename HashKeyGenerator to HashedKeyGenerator for consistency
Making progress on allowing multiple kinds of descriptors to support geo
Virtualize the descriptor so different index types can
serialize the descriptor as it sees fit
Get a polymorphic descriptor type when generating keys so the right key
generation function is called for hashed etc indexes
Move key generators and descriptors to their own files to weaken
header dependencies