Remote Krona resources

By default, Krona resources (Javascript and images) are contained in charts to make them standalone. However, the charts can be made to use the latest available viewing code by referencing remote resources on the KronaTools (or other) server:

ktImport[...] -u http://marbl.github.io/Krona/ [...]

These charts will also be slightly smaller, but will require an internet connection to view.