Add ability to pass timeout parameter to translate api

I sometimes run into the issue of an external API call timing out:
```
ConnectTimeoutError(<urllib3.connection.HTTPConnection object at 0x7f3945ef3680>, 'Connection to api.mymemory.translated.net timed out. (connect timeout=None)')
```

It would be good to have the ability to pass the timeout parameter so code doesn't hang until the connection is closed.