animated cursor

[DreadKnight]

We need to replace "/images/cursor/" with "/images/cursor.png", which is a sprite sheet with 5 frames, going from normal cursor to a hover state cursor, using js there should be a "smooth" animation between the two states, ping-pong style, up to 1 second length, meaning each frame should last 200ms.

Keep in mind the current offset of the cursor, as the finger is not placed in the top-left corner.

[calebj0seph]

Added in b637512, needs a refactor though.

[DreadKnight]

Firefox 14 added a new feature called "Pointer Lock API (primarily aimed at games developers)".
This provides the mouse coordinates, so it should improve performance of the animated cursor and avoid lag.
Maybe Chromium has something similar (or will get in the near future).

[DreadKnight]

@turjuque's code refactoring introduces this as a regression, so it needs to be addressed again.