Add various doc updates

They are still very far from complete.

docs/index.md

@@ -0,0 +1,17 @@
+misc notes for now.  of course this needs to be written up for real.
+
+
+## execution context
+
+The execution context represents facts such as the runtime directory, the
+operating system, hardware, and filesystem layout, distinct from environment
+variables or request-scoped context.
+
+## philosophy
+
+- TODO-DESIGN.md
+- concentric-circles.md
+- nomenclature.md
+- mutability.md
+- commands.md
+- groups-and-roles.md