Fixed StyleMap deserialization

"Pair" inside a StyleMap is an inline list.in KML definition. for
example:

<StyleMap id="styleMapExample">
<Pair>
<key>normal</key>
<styleUrl>#normalState</styleUrl>
</Pair>
<Pair>
<key>highlight</key>
<styleUrl>#highlightState</styleUrl>
</Pair>
</StyleMap>