high level refactoring of directory structure

#### What's this PR do?
1. We've first added some definitions of properties attached to the `this` scope for the DonorsChoose controller, and the SGCreateFromMobileController. (PR #331)

2. We've also refactored some of the closure references to `this` in those same controllers. (PR #332). 

3. We've also changed the directory structure, creating a new `/sms-games` directory, with its own `index.js` routing file and `/models`, `/controllers`, and `/config` directories. (This has also consequently changed the test files.)

4. Finally, some of the helper declared functions in `SGCompetitiveStoryController.js` have been opportunistically moved to the bottom of the file. 

First the high-level directory changes. Then the refactoring of the :japanese_ogre: controller begins. 

#### Where should the reviewer start?
First check out the above changes in the DonorsChoose controller, and the SGCreateFromMobile Controller. Then check out how the directory structure has changed. 

#### How should this be manually tested?
I've manually tested using the following postman testing checklist: 
**Postman testing checklist for all responder controller functionality - 24 Nov 2014**
- [x] donations controller - completing a DonorsChoose donation
- [x] mc routing controller - checking the `yesNoGateway` reportback optin message (does NOT make a database call)
- [x] mc routing controller - `campaignTransition`, transitions user from sign up campaign to actual campaign (NO database calls)
- [x] mc routing controller - `handleStartCampaignReponse`, handles a multiple choice start campaign message
- [x] Tips - delivers tips to user 
- [x] Pregnancy Text
- [x] SGCompetitiveStoryController - beginning a multiplayer game through web opt-ins
- [x] SGCompetitiveStoryController - creating a game through mobile
- [x] SGCompetitiveStoryController - creating an alpha-solo game

#### What are the relevant tickets?
Begins to close PR #332 and #331 (need to make same changes in SGCompetitiveStoryController.)