More godot 4.2 updates

[skyace65]

Supersedes #12

• Updated the gitignore file
• Ran the upgrade mesh tool
• opened and saved .tscn and .tres files which did automatic conversions for Godot 4
• Changed some variable and function names to fix shadowing warnings
• Also changed PoolVector2Array() to PackedVector2Array() and Geometry to Geometry2D as part of that commit
• Replaced get_extents in the polygon_clamp_test file. It was removed and replaced with get_size which is now the full size of a RectangleShape2D instead of half so I divided it by 2