The function will take two arguments: value and time and also parameter - half-decay period.

Example: `exponentialMovingAverage(300)(temperature, timestamp)`
\- exponentially smoothed moving average of the temperature for the past five minutes at the latest point of time.

The state of the aggregate function is current averaged value and the latest time: (v, t).
Whenever new value or new state is appeared, the state is updated as:

```
t_new = max(t_old, t)
v_new = v_old * (1 / exp2((t_new - t_old) / half_decay)) + v * (1 - 1 / exp2((t_new - t_old) / half_decay))
```
(a sort of - did I write the formula correctly?)
(does this way of calculation depend on the order of updates?)
void registerAggregateFunctionsMax(AggregateFunctionFactory &);
void registerAggregateFunctionsAny(AggregateFunctionFactory &);
void registerAggregateFunctionsStatisticsStable(AggregateFunctionFactory &);
void registerAggregateFunctionsStatisticsSimple(AggregateFunctionFactory &);
void registerAggregateFunctionSum(AggregateFunctionFactory &);
void registerAggregateFunctionSumCount(AggregateFunctionFactory &);
void registerAggregateFunctionSumMap(AggregateFunctionFactory &);
void registerAggregateFunctionsUniq(AggregateFunctionFactory &);
void registerAggregateFunctionUniqCombined(AggregateFunctionFactory &);
void registerAggregateFunctionUniqUpTo(AggregateFunctionFactory &);
void registerAggregateFunctionTopK(AggregateFunctionFactory &);
void registerAggregateFunctionsBitwise(AggregateFunctionFactory &);
void registerAggregateFunctionsBitmap(AggregateFunctionFactory &);
void registerAggregateFunctionsMaxIntersections(AggregateFunctionFactory &);
void registerAggregateFunctionHistogram(AggregateFunctionFactory &);
void registerAggregateFunctionRetention(AggregateFunctionFactory &);
void registerAggregateFunctionMLMethod(AggregateFunctionFactory &);
void registerAggregateFunctionEntropy(AggregateFunctionFactory &);
void registerAggregateFunctionSimpleLinearRegression(AggregateFunctionFactory &);
void registerAggregateFunctionMoving(AggregateFunctionFactory &);
void registerAggregateFunctionCategoricalIV(AggregateFunctionFactory &);
void registerAggregateFunctionAggThrow(AggregateFunctionFactory &);
void registerAggregateFunctionRankCorrelation(AggregateFunctionFactory &);
void registerAggregateFunctionMannWhitney(AggregateFunctionFactory &);
void registerAggregateFunctionWelchTTest(AggregateFunctionFactory &);
void registerAggregateFunctionStudentTTest(AggregateFunctionFactory &);
void registerAggregateFunctionSingleValueOrNull(AggregateFunctionFactory &);
void registerAggregateFunctionSequenceNextNode(AggregateFunctionFactory &);
void registerAggregateFunctionSparkbar(AggregateFunctionFactory &);
class AggregateFunctionCombinatorFactory;