Support godot 3.0

[RameshRavone]

Porting HappyCrush to godot 3.0 current master branch will be moved to 2.x branch and godot 3.0 based project will be in master.

This will include

Level Manager
Scene Manager
Game Save (Sqlite GDNative)
Target System
Events
Documentation

Piratically this will be a complete game than a template/demo

[notzoom]

Hello - I clicked the issues tab in order to post this request my self. It would be absolutely incredible if you could make it a reality, this game is really worth the port as it serves as an important reference to that type of game to beginners !

[tzargoth]

Updated for Godot 3.1 in pull request #2