ODBC and database auto detect

[BHare1985]

Make sure ODBC connections will correctly get put into the mapnik xml. Default mssql to ODBC and possibly add support for additional mapnik datasource/connections via plugins to Windwalker. For example using mssql-mapnik would be a simply nodejs package that windwalker would automatically know how to inject the input file where they need it.

Start off with ODBC and mssql and then include from a huge list of possible mapnik plugins that can be used.