Fix infinitely sharp edges isolation

- change topology refiner to check for edge sharpnesses when selecting faces for isolation
- add face-aggregator for edge tags to Vtr::Level
- fix logic in Far::PatchTablesFactory to correctly tag single-crease patches along infinitely sharp edges

note : this fix is a bit of a cludge - barfowl confirms that the vertex crease tags (VTags) are intended to
carry neighborhood information, which they currently do not. we will revisit this shortly and fix the tags,
which will allow us to simplify the traversal logic when isolating topology features.

fixes #369