Add method to retrieve given annotation linked to object.

Method useful to retrieve annotation like modulo annotation
added at import time.
Fix class cast exception.
Fix query to load annotations.
Add tests for modulo retrieval.
Add modulo namespace to constant.
Add test to create XML annotation.
Review existing tests.
Add modulo ns to pojos and add test using modulo ns.
Fix documentation.
Add pixels to the list of supported type. Test added too
Improve Java doc.
scons: Update to version 2.2.0
TEMP workaround for #9813
Image marshal includes zoomLevelScaling
viewport.js $ viewportImage.js pass zoomLevelScaling down to PanoJS
PanoJS handles zoomLevelScaling - default is still 50%
First pass at render_performance page in webtest
Render performance for images in Plate.
Nicer placeholder image
render_performance/image/iid does tiles for big images