Update swagger mixin to better reflect selected or excluded fields

- fixes a bug in parsing excluded fields for these two cases
    - "-firstName" would also show the field "first" as excluded
    - "first-name" would show the field "name" as excluded

- now also excludes unspecified fields in an inclusive select
refactor fields exclusions for swagger
Merge pull request #73 from feychenie/patch-1

Update swagger mixin to better reflect selected or excluded fields