add read-only variation of BindableReactiveProperty and its tests

[Funkest]

• Change ReactiveProperty source to add read-only BindableReactiveProperty.
  • Create ReactivePropertyBase as shared base, which excludes the Value { get; set; } from ReactiveProperty.
  • ReadOnlyBindableReactiveProperty itself doesn't implement Value { get; set; }, but {Binding SomeReadOnlyBindableReactiveProperty.Value} in xaml works through its entity BindableReactiveProperty.
• Naming convension
  • ReadOnlyBindableReactiveProperty? BindableReadOnlyReactiveProperty?
  • ReactivePropertyBase seems unclear and too simple, but I don't have better one.
• Json serialization results as expected like existing ReactiveProperty ones, but deserialization may not.

[neuecc]

ReadOnlyBindableReactiveProperty itself doesn't implement Value { get; set; }, but {Binding SomeReadOnlyBindableReactiveProperty.Value} in xaml works through its entity BindableReactiveProperty.

I didn't understand this part very well, so I would like you to elaborate just a little bit more.

[Funkest]

Tx to reply. I'll add details with wpf sample, please wait.

[Funkest]

• Change ReadOnlyBindableReactiveProperty bindable property to CurrentValue from Value.
  • It's inconvinient to use none-published property Value (This would have confused you, it's my fault), and inconsistent to ReadOnlyReactiveProperty, which pubishes CurrentValue.
• Add sample to sandbox/WpfApp1.

After all, the source seems to be too complex than its merit. I know you have many more important things to do than this, sorry.

[neuecc]

Thank you, I roughly understand. I understand the feeling that it would be better to have ReadOnly, but please allow me to close this for now.