In the resources/properties directory, a plotdefaults.properties file can be added to change plot default settings without modifying the source code (example plotdefaults.properties with default values included). PlotSettings.java has a new method that will read this properties file and overwrite the defaults with the values specified.
updated getting defaults from plot.properties and added unit tests
Merge pull request #99 from rs93/master

Change plot default values via configuration file.

This provides short-term solution to #88