public class RealBlockAverage
This is a helper class to compute block averages. The first time processData is called,
it creates a block of memory the same length as the data passed to the processData() method.
After each call to processData, the user can check the status by calling averageReady().
After an average is computed (averageReady() returns true), no more data will be accepted
until you call the average() method to collect the results.
The averageTimestamp() and averageAbsBlockIndex() return the timestamp and AbsBlockIndex of the
averaged result. The timestamp is that of the first block used in computing the average,
FIXME what to do with AbsBlockIndex