Locate button: configurable scale level to zoom to

[TFimpel]

Many users assume that the locate button will center and zoom the map to their location. Currently the locate button only centers the map (scale level is not affected). Please allow for an (optional) configurable parameter that lets the author specify a zoom level to which the locate button should zoom the map. Thanks!

(Any pointers as to where to change that in my own copy of the code much appreciated, too.)