Bug 803189 - Allow profane words in dictionary but dont suggest them

Fix for [#887777](https://bugzilla.mozilla.org/show_bug.cgi?id=887777) and [#803189](https://bugzilla.mozilla.org/show_bug.cgi?id=803189). This patch adds words that are considered profane to the dictionaries in Gaia.

To prevent profane words showing up in the suggestion list we'll only suggest a word if the input matches the output. This means that it will be possible to type a word like `penis`, whereas it currently gets changed into `Peninsula`.

Also there are a nice bunch of tests.