replacing _.mergeArrays with lodash.union
- introducing the controllers 'actions' convention:
  actions is an endpoint switching between action types
  ex: /api/users?action=search&search=hello
- renaming users.find controller users.actions
introducing the relations.actions controller

Social_graph:
- unexpected cases are thrown by default, or noop+warning
+ cancelFriendRequest
+ removeFriendship
+ delFriendship
avoid sending the error details to the user
+ discard 'method'
- s/remove/unfriend/
+ discardRequest method
- acceptRequest warn on user request accepted after being cancelled
DRYing relations actions
added tests for new methods
updated loadFakeUser method