Lots of work on build-everything

Integration.uproject.tpl.json

@@ -1,5 +1,16 @@
-
 {
+    "about-the-build-system": [
+		"",
+		"The unreal build system generates Integration.uproject.",
+		"That generated file is no good.  Instead, we generate our own,",
+		"as part of build-everything.py",
+		"",
+		"Don't edit Integration.uproject, instead, edit",
+		"Integration.uproject.tpl.json, and then run",
+		"build-everything.py to rebuild.",
+		""
+	],
+
 	"FileVersion": 3,
 	"EngineAssociation": "10.0",
 	"Category": "",