Several additional file and folder types are added to .gitignore:
- VSCode directory for for user and workspace settings.
- *.orig files created by Git on merge conflicts.
- Some artifacts related to the test procedure.
since it replaces characters used in many names and languages with
escape sequences.
Slightly refactor the code for determining author name, to make it
easier to add other version control systems in future (right now it's
just git and hg).
Also, add some binary test artifacts to .gitignore so they don't accidentally
get committed in future.
