global: logging strings are not unicode-friendly

[slint]

The strings used in logging calls in models.py are not unicode-friendly, so when e.g. we create a PID with pid_value = 'DINÂMIA-12345' this info logging call, raises an exception.

The solution is to convert them to unicode strings, i.e.:

-logger.info("Created PID {0}:{1}".format(pid_type, pid_value))
+logger.info(u"Created PID {0}:{1}".format(pid_type, pid_value))