qtvcp -cam_align panel: allow selection of camera number

and some basic error handling of the camera number

Author: c-morley

share/qtvcp/panels/cam_align/cam_align_handler.py

@@ -40,7 +40,14 @@ def __init__(self, halcomp,widgets,paths):
     # the HAL pins are built but HAL is not set ready
     def initialized__(self):
         if self.w.PREFS_:
-            print 'Using preference file:',self.w.PREFS_.fn
+            print('Using preference file:',self.w.PREFS_.fn)
+        if self.w.USEROPTIONS_ is not None:
+            try:
+                num = int(self.w.USEROPTIONS_[0])
+            except:
+                print('Error with cam_align camera selection - not a number - using 0')
+                num = 0
+            self.w.camview._camNum = num
 
     ########################
     # callbacks from STATUS #