first commit
change ball.js to use kinematic equations for projectile motion
change ball.js to account for effects of gravaity
creates RK4.js with projectile motion animation
creates separate files for js code, adds input controls for velocity and key controls to move object
adds particle class to create particle objects; a particle manager; collision manager; input manager; and creates a test suite
organizes code into modules
Merge branch 'master' of github.com:albertaw/Physics