Add README to the examples.

Author: Molorius

example/README.md

@@ -0,0 +1,26 @@
+
+# Examples
+
+These are small examples showcasing some features of the ULP and
+how to access those in ulp-forth. The example_app has some convenience
+features such as a serial reader - for a minimal application, see the
+program in util/minimal_app.
+
+The example program expects ulp assembly in `example_app/main/out.S`.
+This will be compiled by the espressif assembler so the forth should
+be compiled with `--assembly`. This is an esp-idf project. Note that
+the espressif linker has a bug and so has 12 less bytes available.
+
+`cd` into the example_app directory. To compile the blink example with
+subroutine threading, do:
+```bash
+ulp-forth build --assembly --output main/out.S -r 8164 --subroutine ../blink.f
+```
+Or if you want to test the local version of the compiler:
+```bash
+go run ../../main.go build --assembly --output main/out.S -r 8164 --subroutine ../blink.f
+```
+Then compile and flash it with:
+```bash
+idf.py build flash monitor
+```