Removed collection, no current need to persist data-- decreased sprite FPS

# Changes #

### controls.js ###
- changed frame rate from 40 FPS to 20 FPS - seemed to help tremendously with other animations on the page but did make the sprite animation slightly less fluid

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### main.js ###
- turned the background scrolling back on and increased the FPS to 20 - with the changes to the FPS of the sprite, this can now move fluidly without affecting the sprite so drastically
- changed the loadPlatform() function to startPlatformLoad() - just to so it makes more sense since we have a stopPlatformLoad() function
- platform load function is greatly simplified since we no longer need a collection

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### platform-model.js ###
- removed the collection constructor - since we're not currently persisting data (and might not ever need to), it wasn't really needed - the absence of those calls out to the data server should help our memory issues