Been implementing multi-segment position indepndence.

Originally, I was thinking for each data structure instance would have its own list of segment base addresses. I realised while implementing in fact the list of segments could often for a process be the same across all data structure instances – I’m thinking there will normally be only a few shared memory segments, and they will contain all shared data, which means all the data for many data structures and their elements. As such then the multi-segment code needed to be in a little API of its own, so the same instance of segment base address information can be used with all data structure instances.