Added helpers for editing in DataGrid

Added helpers for editing in DataGrid so values can be added while the underlying collection is being updated. Addresses part of issue #8 .

Fixed major bug in ConcurrentObservableDictionary

Fixed a major bug in ConcurrentObservableDictionary where an internal object was being returned instead of the desired value in an indexed accessor. This presented itself as an exception when used in WPF.

Fixed wrong CollectionChanged event arguments

Fixed wrong INotifyCollectionChanged / CollectionChanged arguments. The following classes were supplying the CollectionChanged event with wrong event args:

• ConcurrentObservableDictionary
• ConcurrentObservableHashSet
• ConcurrentObservableSortedDictionary

Fixed exception in AddRange in ConcurrentObservableDictionary

This is a fix for issue #16

• Fixed ConcurrentObservableDictionary, so passing an IEnumerable<,> to AddRange doesn't cause an exception
• Went through entire code base, trimming down the number of static casts used
• Moved units tests out to their own project, as opposed to being part of the manual test app
• Added .NET Core target framework to the unit test project so as all compilation targets will be tested

3.1

PropertyChanged event wasn't being fired for the new EditableCollectionView property.

New EditableCollectionView

New EditableCollectionView available on ConcurrentObservableCollection. See the GitHub project README.md for details.

Fixed a null reference exception

Fixed a null reference exception in a property changed invoker. Fixed it by using the atomic PropertyChanged?.Invoke(…) method.
Removed some cruft from the Auxiliary namespace that hopefully nobody was using.
There's a new BigRational implementation available in Auxiliary, although I'm still using the old one which is now called BigRationalOld.

Made some auxiliary methods and classes public again

Backed out some of previous changes, Decided not to break any code that could be using the Auxiliary stuff.

Made auxiliary methods and classes internal

Had complaints about the generic methods and classes in the Auxiliary namespace being accidently used. Have made these internal.

V3 binaries now signed and have strong name

2.1

Signing the assembly as some dependent projects require a strong name