jquery-i18next: Issue with [prepend] and [append] attributes doesn't work.

Thank you for your great job.

I found problem for the [prepend] and [append] attributes doesn’t work in version 1.0.1. My HTML is following and this works fine in version 0.2.0.

<input id="some-checkbox" type="checkbox" name="some-checkbox-group" value="hoge" checked="checked">
<label for="some-checkbox" data-i18n="[prepend]foo.bar">
  <span class="cool-effect"></span>
  <span class="cool-indicator"></span>
</label>

Because in localze process, jquery causes exception by “#[prepend]foo.bar” selector syntax error. (invalid trimmedKey) https://github.com/i18next/jquery-i18next/blob/master/src/index.js#L43

I know that this change depends on #19 proposal. But I think, the proposal is so far in the different function. Recently, HTML tag is used to make the design rich, too. Therefore, should the library also provides to not changing HTML structure like before?