Support context filtering for FuzzyLookupFactory

FuzzyLookupFactory is great as it can still find matches even if users mis-spell.

Context filtering is also great, as we can only show suggestions based on user's languages, doc types etc

But it's a pity that (seems) FuzzyLookupFactory and context filtering don't work together.

From http://lucene.472066.n3.nabble.com/Is-it-possible-to-support-context-filtering-for-FuzzyLookupFactory-td4342051.html