supported Unicode characters in Python 2

According to the note of curses library documentation:

1. locale is required to be set and
2. the Unicode character to be encoded with the set encoding.

Following the note, using the system's default encoding and encoding the strings. addch is replaced with addstr since multiple characters of encoded Unicode character are needed to be added.
Merge pull request #1 from livibetter/unicode-python2

supported Unicode characters in Python 2