Add dependency injection to label & parent functions

[sWW26]

Using #105 as a basis I've made the label and parent functions injectable (including any resolves from the state and the $scope of the last view).

Added ability for promises to be returned from these functions.

Added ability for states to have themselves as parents.

[coveralls]

Coverage decreased (-4.008%) to 90.698% when pulling 055dc39b8ea785ed313260c1c161a75a3b0d4c95 on woodwardsoftware:feat-injection into e6e92aa5722d8e8036d405bdd9a5b2dea15da31e on ncuillery:master.

[coveralls]

Coverage decreased (-3.8%) to 90.95% when pulling 17e101d4a566cf744e7b93152a50ff60f5f82511 on woodwardsoftware:feat-injection into e6e92aa5722d8e8036d405bdd9a5b2dea15da31e on ncuillery:master.

[sebastienvermeille]

Is this integrated with the current release ?

[qqilihq]

Any news?