show request can have jsonld context in path or params

- [x] show request can have jsonld context in path or params
- [x] updating rails to  4.2.0.rc1; 
- [x] don't have routes or methods for unimplemented actions (editing annotations)
- [x] test against more ruby versions on travis, including the one on the triannon-dev box and the one on my laptop.
- [x] up version to 0.4.0

for #19