URL now contains clicked or typed coords
Set coords from URL
Use DOM ready to initialize stuff.
Merge pull request #40 from MattiasBuelens/dom-ready

Use DOM ready to initialize stuff.
Resetting all boxes changes URL (finishes e839d6f)
Merge commit '58b7' into gh-pages
Crosshairs
Darker crosshair
Add key handler first
Don't handle keys if coords not set
Update URL on arrow keys
Move bounds check into setCoords
Arrow keys stay in bounds
Change point object to length-2 array
List overlaps on coords change
Link to contribute missing image
Larger backing stores
Different crosshair shape per devicePixelRatio
Merge branch 'contrib' into gh-pages
Bind image error to div