Behat i_type should normalise newlines

The following step will behave different between Chrome and Firefox:

    And I type the following text in the "Description" TinyMCE editor:

      """

      This is not important

      """

In Chrome, the newline will be treated as a Paragraph tag
In Firefox it is treated as a Line break.

The i_type function should swap the "\n" character to a W3C ENTER character string: \xEE\x80\x87.