3/pixel copy render dialogs

[yarolegovich]

Changes:

• Implemented floating panel renderer
• The class uses reflection to access dialogs and popups displayed in the given activity
• The class then draws found panels on the bitmap argument. in case of failure a partial result or original bitmap is returned. Our reasoning here is that the only real point of failure is reflection. And if it fails on some device, it's better to receive screenshots without dialogs than nothing.
• PixelCopyDelegate and default fallback strategy are now using floating panel renderer

Falcon was removed because:

• Falcon draws all views it finds in WindowManager, some of them might belong to stopped activities.
• Because of the previous point, dialogs might be handled incorrectly.
• If reflection fails - nothing will be drawn, because it's used even to access decor view of the activity, even though it's available via public API.