Move filter_by_ctnr logic from view to model
Filter key-values by ctnr
default ctnr filtering for DNS objects, plus View objects
Make filter_by_ctnr more consistent
add filter_by_ctnr to interfaces
Merge pull request #310 from murrown/more_filter_by_ctnr

More filter by ctnr, more stuff is filtered. Fully functional. All tests pass.