Remove __melange_queries logging
It causes the local instance to become very slow, as it has to pickle
all queries. A better solution would be to store them in the per
request value store and then add middleware to store that data at
end-of-request.
Coverage: code coverage testing for Python
Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.
For more information, see http://nedbatchelder.com/code/modules/coverage.html