jquery-ui custom images cleanup
jquery-ui cleanup:
 - adding README file and few others from the original package
 - removing themes/flicker
panojs css cleanup
webgateway css cleanup
webclient dusty.css and dusty_ie.css cleanup
moving wrapping JQuerySpinBtn by top level container
fixing embedding dragdiv.mousewheel in viewer
keeping jquery-ui imports of css and js in one location
changing jquery-ui path in webgateway
changing jquery-ui path in viewer
removing jquery-ui-1.8.19.custom.min.js in favor to

3rdparty/jquery-ui-1.8.19/ui/jquery-ui.js
introducing js and css compression using django-pipeline, see #11519

This is first step to make embedding the viewer on static HTML page
examples of how to embed the viewer and minified files
removing GZpiMiddleware as that is used for HTML compression only
Merge remote-tracking branch 'origin/develop' into minify_media_viewer_only
removing unused file
Merge pull request #2195 from aleksandra-tarkowska/minify_media_viewer_only

Minify media viewer only