New message appears when the user cancels an active print while the extruder is heating up to its target temperature. Cancel and Pause buttons are also disabled.
If part preview thumbnail is clicked and the PartPreview window is already opened PartPreview window is brought to front.
changed message box feedback on cancel print.
Rolled back changes made to user feedback when cancelling an active print.
Merge remote-tracking branch 'Greg/development' into development

Conflicts:
	CustomWidgets/PartThumbnailWidget.cs
	StaticData/Translations/Master.txt