Flerpy Birb

It was time to get my Godot juices flowing again. 
What better task than to implement Flappy Bir- I mean Flerpy Birb!

##CONTROLS:
- Left click or Space to Flerp.

###Thanks
- to Samuel Custodio and his Flappy Bird Assets
- to the amazing team behind Bosca Ceoil Blue and for Terry Cavanagh's excellent original tool.
- to the hardworking Godot Foundation and Maintainers
- and as always to @codemonkeyzero for all the help and support