Program will now record any information entered into the
additional information field.

Control Panel
 - adjusted action handler to account for extra text field

DateEntry
 - added extra String variable for memo
 - changed toString method to reflect new variable

Entry
 - adjusted add method to account for extra text field

FileHandler
 - adjusted readData method to account for extra text field
 - added exception catch for empty data files

Lister
 - adjusted add and updateList methods for new text field