Player can jump character to infinity (and beyond?)

W and UP modify the yVelocity of Player to the jumpMod value.
Updated README.md to reflect low motivation.

Due to dwindling interest in this project and horrible sleeping
patterns, I'm reducing scope so that I still want to work on this and
can at least finish *something* for this game.
Added gravity and terminal velocity.

Also started work on checking tiles for collision.
Rudimentary (broken) collision detection.

Need to check X and Y separately to properly get at movement.
Laying ground work for proper movement.

Probably broke somethings; no time to test right now (boo!). Plan to
finish the movement method in TileMap before hitting up the PlayerClass
again to use it (plus testing next time, hopefully).
Continue to modify the setPlayerPosition

Need to: Finish method, change name, test
Fine tuned X movement, undid broken collision code

Redoing movement and collision, planned out changes just need time to
implement.
Created LPEntityPosition

Necessary for using the resolveCollision function that was added to
LPTiledMap.js
Rudimentary collision resolution for X movement.
Minor code clean up.

Removed irrelevant comments, outdated methods.
Fixed x collision for player

Yep.
Minor changes to collision code.

Preparing to start on Y finally.
Fixed Y collision bugs.

Finally got around to debugging y-collision math.
Fixed jumping.