Simple test in README.md does not work

[eblen]

The simple test in the README doesn't work:

run a simple test

cd adaptive/tests/
python test_simple.py

1. The directory name is wrong. It should be 'adaptivemd/tests/'
2. The MongoDB database has to be running, which is not mentioned.
3. It generates an assertion error:

(python2) macbook>python ./test_simple.py
changed state to booting
changed state to running
task succeeded
removing worker dir
Traceback (most recent call last):
File "./test_simple.py", line 89, in
assert(os.path.exists(traj_path))
AssertionError

[jhprinz]

PR #55 addresses the failing example. The README still need to be updated.

[jhprinz]

Thanks for checking.