moved the modernizr placeholder fix from go-local-subscriptions to to-ui

related to https://github.com/GigaOM/go-local-subscriptions/pull/1
wait so we do not need this any more right, if placeholders are supported in IE 10+ and we don't support IE9 or before.

@methnen are you saying we should keep this because the placeholder emulation in 11 (and 10?) isn't good?