Set axis label separator

[xsistema]

Would be nice to have a method to set axis label separator - for example in Lithuania decimal separator is comma. Code to change at AxisTiscksLabels.java - as an example:

String tickLabel = chart.getXAxis().getAxisTickCalculator().getTickLabels().get(i).replace(".", ",");

[timmolter]

issue #915 is already fully covered. Here's what we have:

1. setLocale(Locale) on AxesChartStyler — the correct fix for the reporter's problem. Formatter_Number and Formatter_LogNumber both use NumberFormat.getNumberInstance(styler.getLocale()), which automatically uses the locale's decimal separator (comma for Lithuanian, etc.):

2. setDecimalPattern(String) on Styler — custom DecimalFormat pattern for all numbers on the chart.

3. setXAxisDecimalPattern / setYAxisDecimalPattern on AxesChartStyler — per-axis decimal format patterns.

4. setxAxisTickLabelsFormattingFunction / setyAxisTickLabelsFormattingFunction on AxesChartStyler — full lambda callback for completely custom label generation, which can trivially do .replace(".", ",") if needed:

All of this is documented in README.md:373 under "Customizing Axis Tick Labels".