hidebroken parameter for station lists

[TheLastProject]

Here I am again :)

It's easy to filter broken stations out of the counts in country or tags lists or so, but for requests such as http://www.radio-browser.info/webservice/json/stations/bytagexact/ambient it is not so easy to only get a list of known working stations. Currently, this seems to require downloading the whole broken list and trying to find a match. It would be great if the hidebroken parameter would always be available.