Virtual Views

• made virtual views more closely match Domino views, e.g. regarding ordering of documents and categories
• fixed handling of empty string for category values ("(Not categorized)"), now sorted to the bottom
• fixed comparison of datetime categoryvalues with missing dates (resulting in empty strings)
• new option to change the order of categories and documents in categorized virtual views when constructing the virtual view
• new VirtualViewNavigator methods to sort a set of note ids based on the view order without a full view scan
• added method VirtualViewEntryData.getIndentLevels() for multilevel category values
• excluded docs with $ref field by default from Virtual Views, can be overridden if you really want to analyze them
• more example code in class TestVirtualViews
• bugfixes