Use last print time in the file explorer metadata view instead of the estimated print time (because the estimations are often terrible wrong).
For the display of a current running print the print time already used and the estimated print time left is used as estimation base (will even get corrected while printing).
Also set the cost estimation on it's own line by adding a new line. But only if the object was never printed, to prevent adding an empty line before the cost estimation.
Also repaired some minor whitespace tab issues.

Settings page had old template text for the length/weight toggle. Corrected the hover text to explain the options and fixed settings text to be more intuitive.

Use last print time if available and add new line

correcting hover-text for length/weight toggle

As per #15

Fix description of weight / length calculation checkbox