React-native-router-flux: Change back transition animation

[vnshgrg]

Version

• react-native-router-flux v3.37.0
• react-native v0.38.1

I am using react-native-router-flux for navigation. Is there a way to change the type of transition animation when I go back from a scene to previous scene. If you look carefully, there's a small white space above the navbar which I would like to get rid of. I am thinking if the same animation as transitioning to a new scene can be used to the back transition animation.

[booboothefool]

@vnshgrg https://github.com/aksonov/react-native-router-flux/issues/1202