Represent control family for control enhancements.

[gregelin]

SC-7 (3) control enhancement did not indicate a family in version 0.12.2.

>>> c = compliancelib.NIST800_53("AT-3")
>>> c.family
'AWARENESS AND TRAINING'
>>> c = compliancelib.NIST800_53("SC-7")
>>> c.family
'SYSTEM AND COMMUNICATIONS PROTECTION'
>>> c = compliancelib.NIST800_53("SC-7 (3)")
>>> c.family
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'NIST800_53' object has no attribute 'family'