Fix TSX tileset loading

- Force Platformer example to use TSX tilesets
- Update platformer tileset to include slightly better water animation
Update CHANGELOG
Small improvements to platformer maps

- Add the spikes back to map 2
Fix me.Container bounding box computation

- Was getting NaN because me.Rect `right` and `bottom` properties were adding -Infiity + Infinity
- Solved by returning just the width (or height) when the addition results in NaN or 0
Fix Platformer HUD

- Made the container floating, so it can't be scrolled off-screen
Remove unused Object prototype polyfills
removed the second parameter and emptied the function
Fixed collision shapes in the isometric map (converted polygons to separate segments)

Once rotated and vertically scaled, the shapes are taking <90 degrees
angles (and are therefore becoming concave), which does not work with
the current SAT algorithm
Revert "Fixed collision shapes in the isometric map (converted polygons to separate segments)"

This reverts commit 76da4876f32860e5542fc54746fc52366a2c46e6.
Remove poor optimization that causes multi-shape body collisions to fail in some cases.
Fix a silly bug in the platformer

- Probably not worth the effort... !
- Resets the multijump flag when on the ground
- Increases the magnitude of a jump after falling from a ledge (without using the jump key)

The bug was as follows:

1. Perform a double-jump onto a high platform, and fall from the ledge.
2. While in the air, press the jump key; the player will not jump.
3. Perform a single-jump onto a high platform, and fall from the ledge.
4. While in the air, press the jump key; the player WILL JUMP.

This patch simply fixes the inconsistency, so that the player can always jump after falling from a ledge.
Remove the triangle test entity from platformer
Synchronize grunt and browser tests
Expand me.Color tests
Merge branch 'master' into ticket-144-v2