Incorrect BoundingBox String formatting

[tobrun]

A client has reached out that the bounding box in his request url to route-tiles is being formatted as decimals with comma (instead of a point). The source of this is that String.format uses the device locale.

To fix this issue we need to explitcly need to state a Locale in
https://github.com/mapbox/mapbox-java/blob/master/services-route-tiles/src/main/java/com/mapbox/api/routetiles/v1/MapboxRouteTiles.java#L42

cc @osana, fyi @devotaaabel

[osana]

@devotaaabel could you take care of this