The normal QPalette can be used to determine the icon color so it is
unnecessary to use the flag for custom bright colors here (which is only
intended for colors which are not on the standard QPalette).
* Rely not only on the FolderErrors event
* Request pull errors when opening the dialog
* Use "pullErrors" from FolderSummary
* Move code for directory error dialog into
its own class
This should fix that sometimes obsolete errors
were still displayed or actually present errors
missing.