added util method to extract dataset name from a rsa qualname (that contains some other info also)
Default query when editor is loaded can now be customised via url params.

By including both a dataset and bands url query param, the dataset node
can be customised.  The dataset param needs to be provided in a qualname
format (i.e. rsa:foo/25m), and the bands parameter is a comma separated
list of band ids (i.e. band01,band02,band03).

An example URL is as follows;
SpatialCubeService/app/index.html#?dataset=rsa:test01%2F25m&bands=13117