devlib/utils/misc: improve memoize decorator

Using the wrapt module we can improve the memoize decorator. In fact, it allows
to preserve the attributes of the memoized function, such as signature,
docstring, path to the file where the function is implemented, and so on.

Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>

setup.py

@@ -69,6 +69,7 @@ params = dict(
         'python-dateutil',  # converting between UTC and local time.
         'pexpect>=3.3',  # Send/recieve to/from device
         'pyserial',  # Serial port interface
+        'wrapt',  # Basic for construction of decorator functions
     ],
     extras_require={
         'daq': ['daqpower'],