add experiments/{README.md,_experiment.py}

experiments/README.md

+## How to use
+
+If `from sage.all import *` fails try running
+the python script as `sage -python ./script.py`.
+In the case of bash script use `PYTHON="sage -python" ./script.sh`.

experiments/_experiment.py

+import sys, os, re
+sys.path.append((os.path.dirname(__file__) or ".") + "/..")
+
+import __main__
+_name = re.sub(r".*/", "", __main__.__file__)
+
+print("\n  %s:\n  %s=\n%s" % (_name, "="*len(_name), __main__.__doc__))
+