MeasurementsCsv: rename itermeasurments

Renamed to iter_measurments for readability.
diff --git a/devlib/derived/energy.py b/devlib/derived/energy.py
index 770db88..b3f9c82 100644
--- a/devlib/derived/energy.py
+++ b/devlib/derived/energy.py
@@ -56,7 +56,7 @@
         power_results = defaultdict(float)
 
         # Process data
-        for count, row in enumerate(measurements_csv.itermeasurements()):
+        for count, row in enumerate(measurements_csv.iter_measurements()):
             if use_timestamp:
                 last_ts = row_ts
                 row_ts = time_measurment.convert(float(row[ts_index].value), 'time')
diff --git a/devlib/instrument/__init__.py b/devlib/instrument/__init__.py
index 77ba1d3..cceada6 100644
--- a/devlib/instrument/__init__.py
+++ b/devlib/instrument/__init__.py
@@ -152,9 +152,9 @@
             self._load_channels()
 
     def measurements(self):
-        return list(self.itermeasurements())
+        return list(self.iter_measurements())
 
-    def itermeasurements(self):
+    def iter_measurements(self):
         self._fh.seek(0)
         reader = csv.reader(self._fh)
         reader.next()  # headings