iCal4j 4.1.0 - new accessor behaviour

[benfortuna]

Hi,

In iCal4j v4 we introduced accessors to make it easier to read properties of calendars and components via specific getter methods (e.g. getSummary(), getDtStart(), etc.).

In v4.1.0 we have changed the signature of these accessors such that instead of returning an Optional<?>, as is done for the generic getProperty(String propName), accessors will now return either a property or null if the property does not exist.

This was done to make it easier to use accessors with templating engines and other cases where Optional is not well supported.

Please provide any feedback on this or other changes you would like to see.