feature: Add winforms auto binding to Tables/Flow based controls

[glennawatson]

The following has been added:

• A interface called ISetMethodBindingConverter which allows the bind engine to perform a custom set operation. This is because WinForms often gives you collections where you are meant to do 'Add' operations directly rather than setting them.
• Added two new implementations of the ISetMethodBindingConverter. One for general ContentControls, the other for tables.
• Added a winforms demo based on the main sample.

[codecov]

Codecov Report

Merging #1956 into master will decrease coverage by 0.63%.
The diff coverage is 59.25%.

@@            Coverage Diff             @@
##           master    #1956      +/-   ##
==========================================
- Coverage   59.01%   58.38%   -0.64%     
==========================================
  Files         117      120       +3     
  Lines        4780     4803      +23     
  Branches      678      689      +11     
==========================================
- Hits         2821     2804      -17     
- Misses       1786     1822      +36     
- Partials      173      177       +4

Impacted Files	Coverage Δ
...veUI/Platforms/uap10.0.16299/WinRTAppDataDriver.cs	0% <0%> (ø)	⬆️
...c/ReactiveUI.Winforms/ContentControlBindingHook.cs	0% <0%> (ø)
...rc/ReactiveUI/Bindings/Reactive/ReactiveBinding.cs	75% <0%> (-21.43%)	⬇️
src/ReactiveUI/Expression/Reflection.cs	62.85% <100%> (ø)	⬆️
src/ReactiveUI.Winforms/Registrations.cs	70% <100%> (+7.5%)	⬆️
....Winforms/TableContentSetMethodBindingConverter.cs	8.33% <8.33%> (ø)
...ctiveUI.Winforms/PanelSetMethodBindingConverter.cs	8.33% <8.33%> (ø)
.../Bindings/Property/PropertyBinderImplementation.cs	83.91% <86.76%> (-3.59%)	⬇️
... and 1 more

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[elipriaulx]

Looks good; nice simplifications and cleanup.

[axgdev]

Hi there @glennawatson @gpriaulx! Thank you for the work on ReactiveUI it is great! :)

This commit unfortunately breaks some functionality. If a property value of a binding was null, the framework could (in v9.10.7) cleanly convert it into something appropriate. Example:

this.WhenActivated(disposable =>
{
    this.WhenAnyValue(x => x.FormText)
        .BindTo(this, x => x.Text)
        .DisposeWith(disposable);
});

Please note that this refers to a Form. If for some reason the property FormText is null then an exception is thrown like:

PropertyBinderImplementation: x.Text Binding received an Exception!: System.NullReferenceException: Object reference not set to an instance of an object.
   at ReactiveUI.PropertyBinderImplementation.<>c__DisplayClass10_0`3.<BindToDirect>g__SetThenGet|0(Object paramTarget, Object paramValue, Object[] paramParams) in somepath\src\ReactiveUI\Bindings\Property\PropertyBinderImplementation.cs:line 459
   at ReactiveUI.PropertyBinderImplementation.<>c__DisplayClass10_0`3.<BindToDirect>b__1(TObs x) in somepath\src\ReactiveUI\Bindings\Property\PropertyBinderImplementation.cs:line 475
   at System.Reactive.Linq.ObservableImpl.Select`2.Selector._.OnNext(TSource value) in somepath\src\System.Reactive\Linq\Observable\Select.cs:line 39

[glennawatson]

It's worth probably taking this sort of feedback straight to an issue btw. Closed PR's have a habit of getting lost. Moved it over to one ;)