Movement Fixing

- Input management adjusted to create fluid motion
- Player now has friction
- Player interaction with consumables no longer stops movement
- Player now uses movement state (leftPressed, rightPressed) for
determining necessary move commands

Bug Fixes:
- Removed UpdatePassive() from enemy.h and entity.h
- Removed sf::Event event parameter from several Update() functions
- Inputs are no longer frozen when a key is pressed and released while
another key is held