[Openais] Add a graph hash table to libqb

[Dietmar Maurer]

> The long term goal of this work is to enable a replicated structured
> memory-based key-value storage that maintains consistency after a merge
> from a network partition.  This allows IPC speed reads, and network
> speed writes of key/value pairs with full availability of key/value
> data on all nodes in the network.

Do you plan to make that key-value store persistent? I have a glib
based implementation of such thing which uses Berkeley DB to store
data on each node (some code already posted on the openais list).

The advantage of the 'in memory' architecture is that it is easy
to calculate diffs to do the sync (snapshots/transactions are
simply a copy in memory). The drawback is memory consumption, which
can be huge if there is a large number of key/value pairs. So
a pure database implementation (db4.7 supports snapshots and 
transactions) would be even better?

- Dietmar