remove deprecated classes and specs

Some of the items being removed:

* EventPack
* mappers and helpers related to queries
translate event steam attribute
stream medium JSON projection
Merge pull request #81 from yobennett/remove-deprecated-libs-after-mongoid-3.1.2-upgrade

remove deprecated classes and specs
Merge pull request #82 from yobennett/translate-event-stream-nested-attribute

Translate event stream nested attribute
Merge branch 'dev'