update readme and angle install notes

Readme.md

@@ -0,0 +1,29 @@
+# Install
+
+Clone the repo with the `--recurse-submodules` option.
+
+Get and build ANGLE (see `milepost/ext/angle_install_notes.md`), and put `libEGL.dylib` and `libGLESv2.dylib` in `milepost/bin`.
+
+Cd to orca and build milepost (the platform layer), wasm3 (the wasm runtime), then orca:
+
+```
+cd Orca
+./build.sh milepost
+./build.sh wasm3
+./build.sh orca
+```
+
+Build the sample orca app:
+```
+pushd samples/pong ; ./build.sh ; popd
+```
+This creates a `Pong.app` bundle in `samples/pong` that you can double click to run.
+
+You can also build milepost example apps like so:
+
+```
+cd milepost
+pushd examples/canvas ; ./build.sh ; popd
+pushd examples/perf_text ; ./build.sh ; popd
+pushd examples/tiger ; ./build.sh ; popd
+``` 

milepost

@@ -1 +1 @@
-Subproject commit b27dc615d1465abd33ba6678aa8980c16b08f40b
+Subproject commit f69a6b31ae972fe1decef005f47d048f9e471f19