Use our forked version of winston

This has better logstash support. Hopefully upstream will incorporate
our changes and we won’t have to maintain this for too long.
Added visitingUK prototype
uk river levels redirected through to heroku.app.com from heroku.com
Merge pull request #785 from alphagov/feature/prototype-visas

Added visitingUK prototype
Merge pull request #787 from alphagov/feature/logstash-logs

Fork winston file transport for logstash support
Fix client-side logging in IE9

In Internet Explorer 9, console.log (and similar) do not support
`apply()`.

This commit makes client side logging a no-op because most logging
information that we care about is in the network tab of any good
browser.

In future, proper client side logging is something we may want
to do.