Added Duty Cycle module

Added Duty Cycle module to set, reset and check Duty Cycle of a CPU. This
module makes use of the MSR module

See Issue #11

nrm/coolr/dutycycle.py

+""" DutyCycle Module:
+    This module contains functions to set duty cyle of each cpu in intervals
+    of 6.25% min = 6.25% max(default) = 100%
+
+    Value   -   Duty Cycle
+    0       -       100.0%
+    1       -        6.25%
+    2       -        12.5%
+    3       -       18.75%
+    .
+    .
+    .
+    15      -       93.75%
+    16      -       100.0%
+
+    There are also functions to reset the duty cycle of a cpu and check the
+    current value of duty cycle
+"""
+
+import msr
+
+
+class DutyCycle:
+
+    def __init__(self):
+        self.register = 0x19A
+        self.msr = msr.Msr()
+
+    # set duty cycle of a cpu
+    def set(self, cpu, value):
+        if 0 < value < 16:
+            self.msr.write(cpu, self.register, 16 + value)
+        else:
+            self.msr.write(cpu, self.register, 0)
+
+    # reset duty cycle of a cpu
+    def reset(self, cpu):
+        self.msr.write(cpu, self.register, 0)
+
+    # check current duty cycle value
+    def check(self, cpu):
+        return self.msr.read(cpu, self.register)