refine graph views
This introduces non-continuously scrolling graphs, reduces the update rate of the data, the graphs, and other UI parts, and adds setting schemas.
By default, now, scrolling graphs are non-continuously, but if they are re-enabled they honour the global enable animation setting and are always disabled on power-save mode.
contributes to #48 (closed), fixes #87 (closed), #92 (closed)
Edited by Markus Göllnitz