angles of platforms mess up when alt-tabbing
added logo to splash
bad platform motion
platforms move well on splash screen. No jumping
splash screen adjustments: platforms now controlled by parametric position functions
add tutorial key shortcut on SplashView
added image indicator to SplashView menu
more subtle angular motion on SplashView platforms
Merge branch 'master' into splash_matt
Merge branch 'master' into splash_matt

-- just added test grid image in master; had DEFAULT_SCALES conflict
logo adjustment: change arrow angle to match angle of p
bump version to 0.5.2 for beta to send to David@LM
bump version to 0.5.3 to avoid confusion with 0.5.2 beta build