[issue4016] improve linecache: reuse tokenize.detect_encoding() and io.open()

[STINNER Victor]

STINNER Victor <victor.stinner at haypocalc.com> added the comment:

I wrote a different (and better) patch for tokenize module: moved to 
the issue4021.

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue4016>
_______________________________________