Port Sardana to Python3

• Alba: one month per beamline
• FS-EC has to ensure that we can roll forth and back.
• Part of the code has been ported already.
• Aim: code should run under Python2 and Python3. Therefore we may have to use:

  import sys
  
  if sys.version_info[0] == 3:
      python-3-code
  else:
      python-2-code
  

• Use 2to3 to get some hints where to make adjustments.

  #!/usr/bin/env python
  
  def main():
  
      hsh = {'a':1}
      for k in hsh.keys():
          print "k", k
  
      try:
          a = 1/0
      except Exception as e:
          print( repr( e))
          
      return
  
  if __name__ == "__main__":
      main()
  
  --- 2to3: 
  
   def main():
   
       hsh = {'a':1}
  -    for k in hsh.keys():
  -        print "k", k
  +    for k in list(hsh.keys()):
  +        print("k", k)
   
       try:
           a = 1/0
       except Exception as e:
  -        print( repr( e))
  +        print(( repr( e)))
           
       return