Use prefix 'pystan_' with tempfolder (#628)

Author: ahartikainen

pystan/model.py

@@ -271,7 +271,7 @@ def __init__(self, file=None, charset='utf-8', model_name="anon_model",
         # module_name needs to be unique so that each model instance has its own module
         nonce = abs(hash((self.model_name, time.time())))
         self.module_name = 'stanfit4{}_{}'.format(self.model_name, nonce)
-        lib_dir = tempfile.mkdtemp()
+        lib_dir = tempfile.mkdtemp(prefix='pystan_')
         pystan_dir = os.path.dirname(__file__)
         if include_dirs is None:
             include_dirs = []