Updated to work with nim 0.20

- Attempt to fix deprecated this:self pragma by injecting self to methods and properties (needs more testing)
- Changed import headers to use / (slash) instead of . (period)
- Fixed object branch in godotapigen.nim
- Fixed deprecated nimNode.ident with nimNode.strVal

Fix toGodotName function

Consider procCall calls as special cases, otherwise it gives problems in _init function

Fix infinite recursive call in Godot 3.2

godot/core/rect2.nim

@@ -3,7 +3,7 @@
 import hashes
 
 import vector2
-import internal.godotinternaltypes, internal.godotstrings
+import internal/godotinternaltypes, internal/godotstrings
 import godotcoretypes, gdnativeapi
 
 {.push stackTrace: off.}