minSdk Version seems to be incorrect (in some circum states)

[Hatzen]

First of all thank you for your Lib!

I am trying to run this lib on a Firephone with SDK 19 and the app crashes when opening the zoom activity.
I am getting following exception when clicking onto the ZoomImageView which was created programmatically.

java.lang.ClassCastException: androidx.appcompat.widget.TintContextWrapper cannot be cast to androidx.fragment.app.FragmentActivity
        at ozaydin.serkan.com.image_zoom_view.ImageViewZoom.onClick(ImageViewZoom.java:131)
        at android.view.View.performClick(View.java:4768)
        at android.view.View$PerformClick.run(View.java:19073)
        at android.os.Handler.handleCallback(Handler.java:755)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:145)
        at android.app.ActivityThread.main(ActivityThread.java:5266)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:826)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:642)
        at dalvik.system.NativeStart.main(Native Method)

After some research it looks like the lib does not support minSdk 15 (or at least 19) at least with support lib version used in version 23.0.0 and above.
Full context of crash and solution:
https://stackoverflow.com/questions/38814267/android-support-v7-widget-tintcontextwrapper-cannot-be-cast

[Hatzen]

Fix implemented and tested. Ready for review :)

[hsmnzaydn]

Fix implemented and tested. Ready for review :)

Thanks for your PR :)