OpenSeadragon invocation glitches

[Philip Burns]

There are a few glitches in the invocation of OpenSeadragon.

(1) The unused left and right icons are displayed in dimmed fashion. These icons are for image strips, which are not used in SHC. The should be removed.

Pib has a fix.

(2) The full page expansion icon doesn't work. It appears its behavior is overridden by some other part of the javascript stack..

Pib has a fix.

(3) Panning allows the entire image to be moved out of the display window.

Pib has a fix.

[Philip Burns]

Fixes added to repository code.