Implement ObservableNestedScrollView

[Nebu1eto]

Thanks for Nice Library.
I wanted to use ObservableScrollView and NestedScrollView both, but it doesn't support and Implemented it.

This Request is related at Issue #194. And I add some test code from ScrollView, and also update plugins to latest version. :)

[Nebu1eto]

I found a bug in my code about Saving its states. I'll fix this issue.

[faridgh1991]

Thank you for your effort but it crash on restore instance state with following stack trace:

Class not found when unmarshalling: android.support.v4.widget.NestedScrollView$SavedState
                                                            java.lang.ClassNotFoundException: android.support.v4.widget.NestedScrollView$SavedState
                                                                at java.lang.Class.classForName(Native Method)
                                                                at java.lang.Class.forName(Class.java:308)
                                                                at java.lang.Class.forName(Class.java:272)
                                                                at android.os.Parcel.readParcelableCreator(Parcel.java:2275)
                                                                at android.os.Parcel.readParcelable(Parcel.java:2239)
                                                                at android.view.AbsSavedState.<init>(AbsSavedState.java:57)
                                                                at android.view.View$BaseSavedState.<init>(View.java:20110)
                                                                at com.coinpany.core.android.widget.observablescrollview.ObservableNestedScrollView$SavedState.<init>(ObservableNestedScrollView.java:296)
                                                                at com.coinpany.core.android.widget.observablescrollview.ObservableNestedScrollView$SavedState.<init>(ObservableNestedScrollView.java:281)
                                                                at com.coinpany.core.android.widget.observablescrollview.ObservableNestedScrollView$SavedState$1.createFromParcel(ObservableNestedScrollView.java:312)
                                                                at com.coinpany.core.android.widget.observablescrollview.ObservableNestedScrollView$SavedState$1.createFromParcel(ObservableNestedScrollView.java:309)

[Nebu1eto]

@faridgh1991 Can you describe your dependencies and its version? (Especially Android's support libraries.)

[faridgh1991]

i use support libraries v25.3.1