Fix canvas in Image view.

[jnphilipp]

Fix the canvas in the Image interface.

• fix height to screen height
• stop moving the image out ot the canvas.

[jnphilipp]

The containment feature from jquery doesn't work here due to zooming.

Also there is a button to reset the image.

[cziaarm]

reset image button is a possible workaround

[jnphilipp]

Should be done with #60.