Don't enable visibility of all other features when creating a new feature

In many situations one wants to create and view sequence feature annotation without other annotation being shown - e.g. when sequence features are by default not visible. However, creating a new feature from a selected region automatically enables display of all other features - which can be very confusing. By default, Jalview could *not* enable other discovered features on the alignment (but an option could be provided to rescue the current behaviour)