TimestampWeightedTally.reportLine() method swap two columns

[averbraeck]

In the TimestampWeightedTally.reportLine() method the header does not match with the content. The reportHeader() uses:

"Timestamp-based weighted Tally name", "n", "interval", "w.mean", "w.st.dev", "min obs", "max obs"

while the reportLine() method uses:

... getDescription(), getN(),
formatFixed(getWeightedPopulationMean(), 10), formatFixed(this.lastTimestamp - this.startTime, 10),
formatFixed(getWeightedPopulationStDev(), 10), formatFixed(getMin(), 10), formatFixed(getMax(), 10));

The 3rd and 4th arguments need to be swapped.

[averbraeck]

Repaired bug and committed code.