New features and improvements

• save general and user specific data with new app.storage interface (#967, #978 by @rodja and @falkoschindler)
• introduction of observable dict, list and set (#977 by @falkoschindler)
• allow binding to Mapping type and ignore missing attributes (#981 by @falkoschindler)

Documentation

• Extended and enhanced "generic events" documentation (#984 by @rodja and @falkoschindler )