LOG_LEVEL environment variable to specify log level

gwinc/__main__.py

 from __future__ import print_function
+import os
 import signal
 import argparse
 import numpy as np
@@ -6,7 +7,8 @@ from matplotlib import pyplot as plt
 from IPython.terminal.embed import InteractiveShellEmbed
 
 import logging
-logging.basicConfig(level=logging.INFO, format='%(message)s')
+logging.basicConfig(format='%(message)s',
+                    level=os.getenv('LOG_LEVEL', logging.INFO))
 
 from .ifo import available_ifos, load_ifo
 from .precomp import precompIFO

gwinc/test/__main__.py

@@ -13,7 +13,7 @@ import argparse
 
 import logging
 logging.basicConfig(format='%(message)s',
-                    level=logging.INFO)
+                    level=os.getenv('LOG_LEVEL', logging.INFO))
 
 from .. import load_ifo, gwinc
 from ..gwinc_matlab import gwinc_matlab