Add .gitignore file.

.gitignore

@@ -0,0 +1,23 @@
+
+# Godot-specific ignores
+.import/
+export.cfg
+export_presets.cfg
+*.import
+
+# Mono-specific ignores
+.mono/
+
+# System/tool-specific ignores
+.directory
+*~
+
+# Ignore binary & package
+*.bin
+*.pck
+
+# Ignore lib gdnaive
+libgdnative.*.so
+
+# Ignore temp
+temp/