Merge pull request #18 from SacNaturalFoods/master

fixed totals for grouping queries
Added support for django-custom-field
Do not show properties or custom fields in related models as this
doesn't work anyway and would 500
Added verbose name for slug field for those who don't know what
slug fields are
Update README.md

Updated feature list
Fixed #10
Merge branch 'master' of https://github.com/burke-software/django-report-builder
Just incrementing the version for a new pypi release
added datepicker class to DateField FilterField value inputs