test_utils.py module renamed in tstutils.py

I made this refactoring to avoid confusion with modules that test
other modules (e.g. test_client_daemon.py). since it's not a module
which test utils.py (does not even exist), it's a utility module
for tests.
Merge branch 'master' into test-utils-renaming-refactoring.

Conflicts:
	client/test_client_daemon.py
Merge pull request #65 from iacopy/test-utils-renaming-refactoring

test_utils.py module renamed in tstutils.py