truncating params

[GarrettWarren]

When using the example coordinates, (39.7391536,-104.9847034) from the developers page, the elevation method in elevation.py truncates the inputs so the results are less accurate than the results shown in the example

[jpoehnelt]

Thanks for reporting!

Appears to be an issue in https://github.com/googlemaps/google-maps-services-python/blob/master/googlemaps/convert.py#L34 where the conversion to string truncates the float. This wasn't the intended behavior(default python behavior) from the comments and might need to specify the decimal places before stripping trailing zeros from the string.