Move Visualization/Data selector in Group By form in Menu

This frees the space on top of the main area, which will
next be occupied by the number of authors selected / total.
Move total authors selected / total authors on top of visualization
Expand the list of authors in CSV from the start in data pane
Remove categories from the data pane

The selected categories are already filtered in the select list
for the corresponding filter, like all other categories.
Capitalize important words in visualization/data pane selector
Add 'Authors' after total to clarify
Use 'total-authors' event/property in collect-active-filters

This allows to remove a local field totalAuthors, a function
countAuthors, while subscribing to 'total-authors' instead
of 'authors' for the initialization of the module.
Add constant PREVENT_DEFAULT in dom-utils

This constant, set to false, shall be returned in DOM0 event handlers
to prevent the default action.
Add action link to reset all filters

The link is hidden when all authors are selected (no filter applied).
Add missing export for constant PREVENT_DEFAULT in dom-utils
Merge branch 'enhancements'