Fix some python2-isms in prep for python3

These ones should work in both versions so we don't have to do them as
part of a global change over.

Change-Id: I2177b329d385c50d706a50a750b6c115ea3ea7ae
diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
index 1f1cacd..c3dc1a2 100644
--- a/frc971/control_loops/python/control_loop.py
+++ b/frc971/control_loops/python/control_loop.py
@@ -353,8 +353,8 @@
             '  Eigen::Matrix<%s, %d, %d> %s;\n' % (scalar_type, matrix.shape[0],
                                                    matrix.shape[1], matrix_name)
         ]
-        for x in xrange(matrix.shape[0]):
-            for y in xrange(matrix.shape[1]):
+        for x in range(matrix.shape[0]):
+            for y in range(matrix.shape[1]):
                 write_type = repr(matrix[x, y])
                 if scalar_type == 'float':
                     if '.' not in write_type: