Feature request: Add option to disable smoothing

Please add an option to disable smoothing. This is something which is supported by Gnome System Monitor.

Here is an example CPU plot from Gnome System Monitor (of a stacked chart):
Here is how the plot can look with **smoothing disabled**:

The option to disable smooth plots is within the Gnome System Monitor preferences dialog:

Here is another plot from Gnome System Monitor (not a stacked chart):
And the same kind of plot with **smoothing disabled**:

The rationale for this feature request: I find the CPU plots easier to read with the smooth lines disabled because having slightly less detail makes it easier to identify what is going on with only a quick glance.