Issue 59 new ask post connection fail

Changes in `SubmitLoader.java` resolve issue #59:

- `SubmitLoader.validateResponse` was not correctly responding to HTTPS, only to HTTP
- Avoid `NullPointerException`s in `SubmitActivity.java` by checking if variables are `null` before casting `toString()`
- Various code format fixes in `LoginActivity.java` and `SubmitActivity.java` make code more readable (tabs were pushing code off editor's viewport