In "What’s New In Python 3.0" document, I can read "Removed 
execfile(). Instead of execfile(fn) use exec(open(fn).read())". The 
new syntax has two problems:
 - if the file is not encoding in UTF-8, we get an unicode error. Eg. 
see issue #4282
 - exec() doesn't support newline different than \n, see issue #4628

We need a short function which opens the Python file with the right 
encoding. Get Python file encoding and open it with the right encoding 
is a command pattern.

Attached patch proposes a function open_script() to open a Python 
script with the correct encoding. Using it, execfile() can be replaced 
by exec(open_script(fn).read()) which doesn't have to two binary file 
problems.