com.lafros.juice.alerts 4.0

• alert-related classes moved to separate package, in order that they may be used on their own
• TheAlertsController, IAlertsApp added: allows the app to control the package's behaviour, and impl't some of this itself

• TogPanel bug-fix: subpanel in demo now has new LnF if happened to be concealed when LnF changed

• AlertPanel: add/remove methods now throw IllegalArgumentException instead of IllegalStateException

• AlertPanel: add/remove methods replaced by addAlert/removeAlert, which no longer throw an exception if the specified alert was not found, but instead return a boolean
• AlertPanel: isAlertAdded, isAlertIntrusive added

• TheBeeper: RuntimeException now thrown (rather than printing a line to System.err) if audioclip not found