plot spread points (beeswarm plot)

plotSpread allows creating "beeswarm plots", i.e. point distributions where jitter has been added to the data points to avoid overlap.
It further allows specifying groups within the data to show the distribution of the groups inside a distribution.
plotSpread is most suited to visualizing distributions with small amounts of data points. If the points become too dense, it becomes difficult to appreciate the relative importance of modes of a distribution, in which case "distributionPlot" should be used.

plotSpread uses the excellent "distinguishable_colors" to choose default colors for different categories.

In addition, the .zip file contains "myErrorbar" (a modification of the built-in errorbar), "repeatEntries" for easy repetition of entries in a list, and "isEven" to test whether a number is even. For both "repeatEntries" and "isEven" there are better alternatives on the File Exchange.