More Accurate EstimatedPrintTime and Print time Left + PrintProgress event

Hello,

I added a PrintProgress event (e.g. for updating the LCD with the Progress) and made the Printtime estimation and Print Time left more accurate, e.g. (2:54 Hours calculated Printtime, took 2:51 Hours, Print time Left always told me it might end next to 2:53 Hours) I guess this is accurate enough.
Well heating times are not included.

Requirements for this accuracy is:
1. A good feedRateMultiply value in the settings. This value shall compensate the acceleration for me a value of 0.75 made the good estimations from above.
2. The gcode file must have been analysed before Selecting. 
ATTENTION not printing it really must have been analysed before selecting, maybe I change that.

Hope this helps to get better estimations.