gitignore: keep these in one place in the code
py3: Use double backspace instead of ur-string literals
i18n: Remove translate.i18n

This is currently unused. It is also causing problems on python 3 due to
the use of __builtins__. Since we don't really need it at the moment, it
is safe to remove.
py3: tests: Use double backspace instead of ur-string literals
trados: Use BeautifulSoup4 instead of obsolete version 3