Start using to oslotest

oslotest provides a BaseTestCase class then enables proper capturing of
stdout, stderr and logging streams during a test run. We will take
advantage of this capability in the near future.

Change-Id: I16761053f631e709224eee813dc0f423f06c8870
Allows override of stdout/stderr/log capturing

During a test run stdout, stderr and log messages are being captured. If
the test fails all three will be printed out so that can be inspected.
Each stream has an environment variable that can be used to stop it from
being printed at the end of a test run by setting its value to 0. This
is in line with what many of the other project are already doing.

Environment variables:

 - OS_STDOUT_CAPTURE for stdout
 - OS_STDERR_CAPTURE for stderr
 - OS_LOG_CAPTURE for logging

Change-Id: I2fed99069950b839e060297026c8e06cbd45bb98
Merge "Start using to oslotest"
Merge "Allows override of stdout/stderr/log capturing"