Cannot copy worksheets with non-ascii titles
*Created originally on Bitbucket by [4744020502 (eson)](https://bitbucket.org/%7B36a19536-5cff-47b4-8a68-52a2a2771298%7D/)*
```
#!python
Traceback (most recent call last):
File "create_temp.py", line 236, in <module>
CopySheet(wb,sn, "12")
File "create_temp.py", line 168, in CopySheet
s = wb.copy_worksheet(ws)
File "/usr/lib/python2.7/site-packages/openpyxl/workbook/workbook.py", line 364, in copy_worksheet
new_title = "{0} Copy".format(from_worksheet.title)
UnicodeEncodeError: 'ascii' codec can't encode characters in position 3-4: ordinal not in range(128)
"{0} Copy".format(from_worksheet.title) replace with u"{0} Copy".format(from_worksheet.title)
that is working well
```
issue