Don't use TableSelectorImpl implementation details in TableSelectorActivity.

Don't use TableSelectorImpl implementation details in TableSelectorActivity.

This is part of a change to get navigation buttons in the details view
but it should have been done this way from the start.

* src/main/java/org/glom/web/client/activity/ListActivity.java: Update
for method name change in TableSelectionView.
* src/main/java/org/glom/web/client/activity/TableSelectionActivity.java:
Create TableChangeEvent and set the browser title using the
TableSelectionView API.
* src/main/java/org/glom/web/client/ui/TableSelectionView.java:
* src/main/java/org/glom/web/client/ui/TableSelectionViewImpl.java:
Change getSelectedTable() to getSelectedTableName(). Add
getSelectedTableTitle().