Refactored the application trait code.

The App trait has been refactored to support both CLI- and GUI-based
applications (simulations that run as batch jobs on servers do not
require GUI facilities). Added a LogWindow element to which standard
output and standard error output in GUI applications are directed.
Corrected some resource element namess in the Simulation and
OutOfEventsException elements.
Bumped Scalatest to latest release (2.2.1).