Override locale to always use UTF-8

Description

Python's open() function uses a locale-dependent encoding when files are opened in text mode. This caused some problems with unicode characters when the locale reverted to ASCII.

The aim of this is to make the default encoding for files consistently UTF-8, regardless of the environment variables.

How Has This Been Tested?

TBD

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the code style of this project.

Reviewers

@schmidtp @hammerd @danilevc @roscar