resolving jshint issues with tabbing and use of "this" in app/scripts/app.js

### Issue
GIVEN a clean, global install of generator-meanstack
AND GIVEN a new scaffold created with yo meanstack
AND GIVEN options are chosen as
  * are you planning to deploy this project on Heroku: Y
  * prefer a stable version of AngularJS: Y
WHEN the command - grunt - is issued against the project root
THEN the output indicates errors generated by JSHint against a single file - app/scripts/app.js
   * several lines indicate unexpected tab spacing
   * the use of "this" as a parameter to the call method is indicated as a possible strict violation

### Resolution
   * forked the repository
   * edited the app/templates/app/scripts/app.js file:
      * adjusted all tab spacing to follow convention
      * removed the "this" reference as it is verbose in the given usage

### Testing
   * global uninstall of generator-meanstack - i.e. npm -g uninstall generator-meanstack
   * link forked repo - i.e. from cloned fork: npm link
   * created a test folder - i.e. mkdir meanstack-test && cd meanstack-test
   * generated a scaffold with the updated generator - i.e. yo meanstack
   * successfully ran the command - grunt - with no errors
![localgenerator_cleanrun](https://cloud.githubusercontent.com/assets/3719046/3486245/27cef122-042a-11e4-88b0-da021cdf4365.png)
![successfulbuild_gruntnoerrors](https://cloud.githubusercontent.com/assets/3719046/3486246/2d1348ae-042a-11e4-9a9e-b8479a637760.png)