Support WKT formatted Geo Shapes

[jbaiera]

Geo shapes can be specified in either a JSON format, or as a WKT string. At the moment, ES-Hadoop only supports reading the JSON format value, since it translates directly to a Map-like structure. Additional parsing rules should be added to support reading geo shape types that are represented in WKT format.

[sfalquier]

This is also a problem for me. It would be great if it could be fixed.