Assocs the data to the given keyword which matches the corresponding namespaced or
unnamespaced keyword. The keys of the given map should be keywords and
there should be only one possible match, otherwise an exception is thrown.

If the key is not present in the map, returns the original map.

Returns the key which matches to the given keyword after unnamespacefying.
The keys of the given map should be keywords and there should be only one
possible match, otherwise an exception is thrown.

This helper can be useful if you want to build a function which supports multiple
namespaced keywords that contain the same regular part. For example, getting the name of both
:product.domain.player/name and :product.domain.task/name is easy with get-un.

The data can be a map, a vector of maps or a keyword. In all cases, it adds a namespace
 to the keywords.

 Options is a map with the following keywords:
 :ns        Keyword, which provides the default namespace to be used (if exceptions are not provided).
            If data is a keyword, this is the only option which is taken into account.
 :except    Set of keywords. The name of the keywords are not modified.
 :custom    Map of keywords present in the given data. These keywords are named differently.
 :inner     Map, which provides options for namespacefying inner maps and vectors.

Example:

(def data {:name "player1" :id 1 :tasks {:id 666 :time 5} :points 7 :foobar nil})

(namespacefy data {:ns :product.domain.player
                   :except #{:foobar}
                   :custom {:points :product.domain.point/points}
                   :inner {:tasks {:ns :product.domain.task}}})
=> {:product.domain.player/name "player1"
    :product.domain.player/ip 1
    :product.domain.player/tasks {:product.domain.task/id 666
                                  :product.domain.task/time 5}
    :product.domain.point/points 7
    :foobar nil}

Converts namespaced keywords to regular keywords. The data can be a map, vector of maps or a
 keyword.

Options is a map with the following keywords:
:except       Set of keywords. The name of the keywords are not modified.
:custom       Map of keywords present in the given data. These keywords are named differently.
:recur?       Unnamespacefy all keywords recursively (all nested maps and vector of maps are touched)