Files are only read as UTF-8, add encoding detection

[nbowden045]

I tried to set it up with a gradebook file and got a Unicode Error message.

It turns out my files are encoded with us-ascii, maybe there could be a feature added to detect file encoding and open with the right encoding (not only support utf-8, python's default)

Some ideas: https://stackoverflow.com/questions/436220/how-to-determine-the-encoding-of-text, which would involve new dependencies on chardet or python-magic (libmagic that backs the bash file command)

OS:
Windows 11

Package Versions:

csvgrader==0.1
numpy==2.0.1
pandas==2.2.3
pip==25.0
python-dateutil==2.9.0.post0
pytz==2024.1
setuptools==75.8.0
six==1.16.0
tzdata==2023.3
wheel==0.45.1