BarChart crashing when changing data on runtime

[PavlosTze]

The BarChart crashes when changing the data on runtime (if the number of datapoints is changed). This is because of the following code:
On BarChartView.kt:
` if (barsColorsList == null)
barsColorsList = List(frames.size) { barsColor }.toList()

        if (barsColorsList!!.size != frames.size)
            throw IllegalArgumentException("Colors provided do not match the number of datapoints.")`

If someone tries to change the data on runtime, by clicking a filter button for example, the frames.size is changed, but the barsColorsList!!.size isn't, because of the above code only checks for nullability so it doesn't update the barsColorsList.

Will submit a PR to fix this.

[PavlosTze]

@diogobernardino Just created a PR to fix this issue:
#310