BF: reincarnate logging

Many messages just need to be downgraded to DEBUG level and additional
care should be taken about logging configuration for other modules we use.
But in general -- we do need logging and should be able to control it from
the environment variables for e.g. tuning it up quickly during test runs

Author: yarikoptic

heudiconv/__init__.py

@@ -1,5 +1,12 @@
 # set logger handler
 import logging
-logging.getLogger(__name__).addHandler(logging.NullHandler())
-
+import os
 from .info import (__version__, __packagename__)
+
+# Rudimentary logging support.
+lgr = logging.getLogger(__name__)
+logging.basicConfig(
+    format='%(levelname)s: %(message)s',
+    level=getattr(logging, os.environ.get('HEUDICONV_LOG_LEVEL', 'INFO'))
+)
+lgr.debug("Starting the abomination")  # just to "run-test" logging