Parametrize isBadQuery

[FreCap]

I'm using an ajax elastic search, and I had to disable it globally to allow elastic search work:
$.Autocomplete.prototype.isBadQuery = function() {
return false;
};

It would be nice if you could parametrize it.

[tkirda]

It gets quite complex if serviceUrl is dynamic. Added ability to disable this via configuration: preventBadQueries: false.