add Leg and Hexapod classes

software/rpi/leg.py

@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+
+class Leg:
+    def __init__(self,
+                 id,
+                 junction_servos,
+                 correction=[0, 0, 0],
+                 constraint=[0, 180]):
+        self.id = id
+        self.junction_servos = junction_servos
+        self.correction = correction
+        self.constraint = constraint
+
+    def set_angle(self, junction, angle):
+        set_angle = min(angle+self.correction[junction], self.constraint[1])
+        set_angle = max(set_angle, self.constraint[0])
+        self.junction_servos[junction].angle = set_angle