C implementation now uses 1-bit storage

[PeterOvermann]

The latest C implementation of Dyadic Memory and Triadic Memory is now based on 1-bit storage locations.

This reduces memory consumption to 1/8, compared with the previous version which was based on 8-bit memory counters.

In Triadic Memory, the query performance changed: Querying for z became somewhat slower, while querying for x and y is now much faster.

An advantage of 1-bit storage is that the same association can be stored again and again without changing the state of the memory.

Deletion from memory is no longer supported.

I've archived the original implementations as "Version 1".