Update styles/osm2pgsql_google_polygon_map.qml

Added grass rendering for high zoom levels when more detail is needed on the map. 
Update styles/osm2pgsql_google_line_map.qml

This update mostly updates the line layer so that it looks good all scales. To do this new styling for different zoom levels were created. 


Updated Labeling 
(larger labels and motorway ref labeling) 
Updated Style 
(reordered roadway based on class)
(recolored trunk to closer match primary roads)
(recolored motorway link to match motorways)
(updated style to allow for optimal viewing at different zoom level)
Merge pull request #3 from aplannersguide/master

Updated: Google themed QGIS styles for OpenStreetMap data loaded with osm2pgsql tool