Prepare for Django 1.10

[ebrelsford]

I receive three warnings on the console when using django-report-builder that are related to deprecations coming in Django 1.10, figured I would note these here so we're not surprised when it gets here.

/.../python2.7/site-packages/report_utils/model_introspection.py:41:
RemovedInDjango110Warning: 'get_all_field_names is an unofficial API that has been deprecated. You may be able to replace it with 'get_fields()'
    all_fields_names = model_class._meta.get_all_field_names()

/.../python2.7/site-packages/report_utils/model_introspection.py:43:
RemovedInDjango110Warning: 'get_field_by_name is an unofficial API that has been deprecated. You may be able to replace it with 'get_field()'
    field = model_class._meta.get_field_by_name(field_name)

/.../python2.7/site-packages/report_utils/model_introspection.py:44:
RemovedInDjango110Warning: Usage of field.related has been deprecated. Use field.remote_field instead.
    if field[2] and not field[3] and not hasattr(field[0], 'related'):