Fix strange WPF quirks in VS extension

[atlaste]

The information doesn't always seem to update in the VS extension. Upon closer inspection it apprears something fishy is going on...

Relevant code: Coveragereport.xaml.cs, line 52-58

WCF should update lists in an ObservableCollection. While this works, apparently the DataGrid stops functioning when we use this. Using a normal List works seems to work, but doesn't update anymore.