Powerpoint with unicode characters makes OpenLP crash

[Tomas Groth]

The traceback below was reported on the support system. The problem is that if a PPT contains unicode characters we get into problems when we save the slide notes and titles to a text file, because python on windows defaults to encode in cp1252. The fix is to use utf-8 encoding when saving the text files.

*OpenLP Bug Report*Version: {'version': '2.1.2', 'build': None, 'full': '2.1.2'}
--- Details of the Exception. ---

Uploading a presentation file. MS Power Point.

--- Exception Traceback
---Traceback (most recent call last): File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\core\lib\mediamanageritem.py,
line 321, in on_file_click File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\core\lib\mediamanageritem.py,
line 377, in validate_and_load File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\plugins\presentations\lib\mediaitem.py,
line 186, in load_list File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\plugins\presentations\lib\powerpointcontroller.py,
line 133, in load_presentation File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\plugins\presentations\lib\powerpointcontroller.py,
line 410, in create_titles_and_notes File
D:\OpenLP_Development\OpenLP_Code\2.1\openlp\plugins\presentations\lib\presentationcontroller.py,
line 335, in save_titles_and_notes File
c:\Python33\lib\encodings\cp1252.py, line 19, in
encodeUnicodeEncodeError: 'charmap' codec can't encode character
'\uf04a' in position 11: character maps to <undefined>