Update the output

[ghar1821]

Currently ChronoClust produces a csv file showing the cluster id of each data point as well as the values of the data point. To simplify the output, it should just produce a txt file or return an array containing the cluster id for each data point.

To do this, we need to make sure that the order of the output matches the order of the dataset, i.e. 1st element in the output array must be the cluster id for the very first data point in the dataset. This feature is currently already available by storing the id of the data point when they're read in. Thus it shouldn't be too hard to simplify the output.

We should also rename the result.csv file to metadata.csv as it's theoretically metadata.