ISIS-406, ISIS-416, ISIS-417: updating poms; 'select all' checkbox; disable concurrency checking; make spinning-icon configurable; remove defunct code

* updating poms to latest snapshot;
* select all on standalone tables in wicket viewer
* moved spinning-icon.gif (for veil) out into WEB-INF dir, so pluggable
* fixed some concurrency issues.
ISIS-418: deleting the isis-site-skin