Replaces use of numpy.random.RandomState in coordinate encoder with Rand...

...om class from NuPIC.
Very valid concern. Open to suggestions for alternatives but seems fine to me:

```
In [5]: def test():
   ...:     s = time.time()
   ...:     n = 0.0
   ...:     for _ in xrange(100000):
   ...:         n += int(int(hashlib.md5("34,324,23").hexdigest(), 16) % (2 ** 64))
   ...:     print time.time() - s
   ...:     print n
   ...:

In [6]: test()
0.19149017334
3.6612833101e+23
```