Valid run filenames for Windows (#137)

Convert datetime into valid string filename for Windows

all/experiments/writer.py

@@ -14,8 +14,6 @@ class ExperimentWriter(SummaryWriter, Writer):
     tagging the run with a combination of the agent name, the commit hash of the
     current git repo of the working directory (if any), and the current time.
     Also writes summary statistics into CSV files.
-
-
     Args:
         experiment (all.experiments.Experiment): The Experiment associated with the Writer object.
         agent_name (str): The name of the Agent the Experiment is being performed on
@@ -24,7 +22,7 @@ class ExperimentWriter(SummaryWriter, Writer):
     '''
     def __init__(self, experiment, agent_name, env_name, loss=True):
         self.env_name = env_name
-        current_time = str(datetime.now())
+        current_time = datetime.now().strftime('%Y%m%d-%H%M%S')
         os.makedirs(
             os.path.join(
                 "runs", ("%s %s %s" % (agent_name, COMMIT_HASH, current_time)), env_name
@@ -51,7 +49,6 @@ def add_schedule(self, name, value, step="frame"):
     def add_scalar(self, name, value, step="frame"):
         '''
         Log an arbitrary scalar.
-
         Args:
             name (str): The tag to associate with the scalar
             value (number): The value of the scalar at the current step