ISIS-400: render buttons close to properties.
ISIS-400: factored out AdditionalLinksPanel, now used throughout

ie all subclasses of ScalarPanelAbstract, and also by entity collections as well.
ISIS-396: fix for parsing of BigDecimal values.

was truncating in some situations... fixed impl.
ISIS-396: further fix for BigDecimal parsing

when an action parameter.
ISIS-402: bulk actions now shown for prototype and exploring modes.

ie @Bulk and @Prototype now can be used in conjunction.
ISIS-403: improved bookmarking in Wicket viewer

@Bookmarkable annotation
Bookmark Panel moved to side.
ISIS-403: further improvements on bookmark; also fix to fieldset styling

* working towards hierarchical bookmarks
* fieldsets now distinguished separately
ISIS-403: bookmarks now organize themselves into hierarchy

as per @Bookmarkable(AS_ROOT) or @Bookmarkable(AS_CHILD).
ISIS-403: can now remove individual bookmarks from panel

Bookmark panel now also appears on home page and about page

Also some minor CSS restyling...
* made margins a little smaller
* float object actions to the left, not right (after title)
* increased font size for drop-down box
* increased font size for string panel