ISIS-731: fix for bulk actions

Take a copy of the action model that generates the standalone collection.
ISIS-732: check semantics of action before re-executing

...when refreshing the collection after invocation of a bulk action.
ISIS-734: download blob/clob in same window

... rather than different tab (which is the behaviour for actions returning a URL).
ISIS-735: fix for ToDoItem#notYetCompleted()
ISIS-733: JDO objectstore version timestamp leave as null.
Merge branch 'master' into prepare/isis-1.4.0-RC1
ISIS-735: porting app fix over to archetype

... to prepare/isis-1.4.0 branch (for 1.4.1 patch releases)

Also moving 1.5.0-snapshot back to 1.4.1-snapshot for jdo and wicket.
[maven-release-plugin] prepare release isis-objectstore-jdo-1.4.1
[maven-release-plugin] prepare for next development iteration
[maven-release-plugin] prepare release isis-viewer-wicket-1.4.1
[maven-release-plugin] prepare for next development iteration