Exceptions and Panics

Miranda should never stop.  Ever.

This means my blithe strategy of printing a stack trace and calling System.exit in response to an exception cannot hold.  Instead, most threads must continue and instead throw a Panic when things get really bad.

A Panic is like an exception, except that the system treats a panic as a request to shut down instead of automatically printing a stack trace and exiting.

I have also created a panic method on the Miranda class.  If the method returns at all (the default behavior is to call System.exit but this will change) it returns a boolean to indicate if the system as a whole is panicking, or if the caller should try and keep going.  The system may attempt to shutdown instead of calling System.exit so correctly handling the response to a call to Miranda.panic is important.