python: Servo: add Navio+ support

Add root check
Add Navio+ entry and add shield auto choice

Author: Igor Anokhin

Python/Servo.py

@@ -1,21 +1,32 @@
-import sys
 import time
+import os;
 
-import navio.pwm
-import navio.util
-
-navio.util.check_apm()
+import navio.Common.util
+import navio.Navio2.RCOutput
+import navio.Navio.RCOutput
 
 PWM_OUTPUT = 0
 SERVO_MIN = 1.250 #ms
 SERVO_MAX = 1.750 #ms
 
-with navio.pwm.PWM(PWM_OUTPUT) as pwm:
-    pwm.set_period(50)
-    pwm.enable()
+def get_pwm():
+	if (navio.Common.util.get_navio_version() == "NAVIO2"):
+		return navio.Navio2.RCOutput(PWM_OUTPUT)
+	else:
+		return navio.Navio.RCOutput(PWM_OUTPUT)
+
+if (os.getuid() != 0):
+    print "Not root. Please, launch like this: sudo python Servo.py"
+    exit(-1)
+
+navio.Common.util.check_apm()
+
+with get_pwm() as pwm:
+	pwm.set_period(50)
+	pwm.enable()
 
-    while (True):
-        pwm.set_duty_cycle(SERVO_MIN)
-        time.sleep(1)
-        pwm.set_duty_cycle(SERVO_MAX)
-        time.sleep(1)
+	while (True):
+		pwm.set_duty_cycle(SERVO_MIN)
+		time.sleep(1)
+		pwm.set_duty_cycle(SERVO_MAX)
+		time.sleep(1)