Opened files are immediately set as changed

[Mailaender]

https://www.eclipse.org/lists/chemclipse-dev/msg00068.html mentioned this before as it irritates every new user. Opening a file and closing it will always cause a nag dialog to save non-existing changes, which is annoying and also unexpected. This seems to be a quick hack to force enable the save button. However, simply clicking on the open editor already enables save as.