full support for MultiGeometries

fix bug #30 and add support for MultiLineString

1) PositionsAdapter.parsePositions() recognizes the position in the array (within the recursion of the method)
thus it is possible to remove the workaround for bug # 15 in GeometryAdapterFactory.buildPolygon() and GeometryAdapterFactory.buildMultiPolygon()
2) GeometryAdapterFactory: buildMultiLineString() added and used in buildGeometry()