Add enhancement proposal in TODO list
Wrapper display error handler is now 'replace'
Rewrite $SAVEPATH setting's docstring.
Fix bug on Path().read() method.

bin_mode was implicitly changed inside of method. So
event when bin_mode was False, the read() method
sometimes was returning bytes() instead of str() object.

Now, when bin_mode is set, bytes() is always returned,
and when bin_mode is unset (default), str() is always returned.
Add wew setting $PAYLOAD_PREFIX (fixes issue #3).