Bug: NPE in GeneralOptionsPane

[bitfist]

I just noticed an NPE while saving the settings

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException: Cannot invoke "String.trim()" because the return value of "javafx.scene.control.TextField.getText()" is null
	at org.markdownwriterfx.options.GeneralOptionsPane.save(GeneralOptionsPane.java:170)
	at org.markdownwriterfx.options.OptionsDialog.save(OptionsDialog.java:122)
	at org.markdownwriterfx.options.OptionsDialog.lambda$new$0(OptionsDialog.java:93)

addonsPathField.getText().trim() produces the NPE