Serialization of stream aggregates.

Serialization for the following stream aggregates has been implemented (TTimeSeriesTick, TTimeSeriesWinBuf, TMa, TEma, TVar). Additionally the follwing aggregates have been implemented (TWinBufCount, TWinBufSum, TWinBufMin, TWinBufMax). TMa and TVar have been tested and debugged (now they work even if the buffer gets emptied during removal of old records).