Minor bug fix for test-runner

- ret variable not properly set on return from wp_test_execute_tests.
  This is a regression from commit f0313a
- Add check for test execution to display memory stats.
Memory stats printed to stdout on shutdown

- Add wp_memory_print_stats call to wp_memory_shutdown_atexit to ensure
  memory statistics are printed to the console window at shutdown,
  regardless of call-method (tests or engine)
Add wp_fs module

wp_fs.w:
- Simple wrapper around file system functions
  - Add wp_get_user_home_folder function and basic module load/unload
    framework
  - Stub out object and operations; no body code added at this time

wp_scene.w and wp_tegen.w:
- Consolodate HUD objects into a separate class
- Add startup/shutdown module functions
- Stage set for screen and frame capture