Add dummy micropython module to enable mandel.py run with CPython.

examples/mandel.py

+try:
+    import micropython
+except:
+    pass
+
+
 def mandelbrot():
     # returns True if c, complex, is in the Mandelbrot set
     @micropython.native

examples/micropython.py

+# micropython module placeholder for CPython
+
+# Dummy function decorators
+
+def nodecor(x):
+    return x
+
+byte_code = native = viper = nodecor