Minimal CircuitPython port documentation

Author: ccattuto

advanced/circuitpython/README.md

@@ -0,0 +1,11 @@
+## Compiling CircuitPython
+```
+cd port-riscv-emu.py
+make
+```
+
+## Running CircuitPython
+```
+./riscv-emu.py --timer=mmio --ram-size=4096 --uart --blkdev=advanced/circuitpython/riscv-emu.py/build-riscv-emu.py/circuitpy.img advanced/circuitpython/riscv-emu.py/build-riscv-emu.py/firmware.elf
+```
+