GET shows

**Terminology**: Spinitron defines a *show* as a radio program. A show can have one or more *schedules*, each of which may specify either an *occurence* or a *repetition*, which represents a set of occurences. Thus scheduled shows have occurences that, for example, may be displayed in a calendar. In the response, `items` is an array of objects representing occurences of scheduled shows. You may optionally filter `items` to a datetime *range* by including in the request {start} and/or {end} parameters, both of which must be no more than one hour in the past. An occurence starting at {end} is included in the reponse. `itmes` can include occurences that begin *or* end within the filter range. A show that goes on air before {start} appears in `items` if it ends *after* but not *at* {start}. An occurence starting at or before {end} is included. If the request omits the {start} parameter, the server sets its value to the current time so that the filter range's start is always defined. If the request specifies {end} then the requested range is *bounded*, otherwise it is *unbounded*. For a bounded request, `items` includes *every* occurence of all shows occuring in the range. The only difference between objects in `items` representing a given show will be the `start` field value. For an unbounded request, `items` includes *only one* occurence per show, specifically, the next occurrence after {start} of all shows occuring after {start}. Use an unbounded request to get a straight list all shows. Use a bounded request to get a calendar/agenda of shows expanded into occurrences by thir shedules and repetitions. Objects in `items` are ordered first by `datetime` and then by `id`.