Change the date format in the state filename & support state variable of type numpy.ndarray

[h4k1m0u]

• Windows doesn't accept colons in the filenames, and couldn't create the state file.

Here is the error I'm getting when I run the salesman.py example:

File "c:\github\simanneal\simanneal\anneal.py", line 63, in save_state
    with open(fname, "w") as fh:
IOError: [Errno 22] invalid mode ('w') or filename: u'2016-06-23T01:13:58_energy_7060.97080007.state'

• The second error concerns the case when a numpy.ndarray variable is used as a state variable, and is shown below:

File "c:\github\simanneal\simanneal\anneal.py", line 46, in __init__
    if initial_state:
ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

[perrygeo]

Thanks, this looks great @h4k1m0u