Added accumulation line indicating sum of QQEcho weight, simulating look-back & decay.
Added input for 'QQE Trigger', which only determines level for color-change of that accumulation line.
Added inputs for Decay Start Bar & Decay Rate.
Not added/relevant is an input for lookback bars.
Accumulation line simulation here will differ slightly from IMQ strategy which has lookback-input, in that this indicator is continuously accumulating & decaying, whereas the strategy clears the accumulation with a new lookback when newly seeking next trade.