Save support for defined visualization groups

[sjaenick]

In gitlab by @sjaenick on Nov 10, 2015, 20:42

With a large number of datasets, a lot of initial effort is necessary to setup and define an appropriate grouping for visualization.

ToDo:

• save current set of defined groups to user directory
• restore previous (named?) set of groups
• handle deleted datasets (at least notify user)

[sjaenick]

issue refers to different component