Skipped parts should be omitted from the Remaining Time estimate

[prdoyle]

Is your feature request related to a problem? Please describe.
When I skip a part, the time it takes to print that part seems to be still included in the Remaining Time estimate. I believe this is incorrect, because skipped parts shouldn't consume much (if any) time.

Describe the solution you'd like
I'd like the Time Remaining estimate to be adjusted to correctly account for the effect of skipping a part.

Describe alternatives you've considered
In the Prepare tab, pick the skipped part and toggle it to not Printable. Re-slice the plate. Use the new time estimate to guess when the print will finish.