in version 3.0 _s_count function does not apply filters to query

[lapierreni]

Just a heads up, it looks like the _s_count function doesnt add filters to the count cls.query.count() call. I fixed this locally in our code by overriding the function with:
count = cls.jsonapi_filter().count()

Simple PR to add this: #147

[thomaxxl]

Thanks, I will fix this the next days.