Introduces DosomethingCanadaSsoUser class.

#### What's this PR do?
- Introduces `DosomethingCanadaSsoUser` class based on common `DosomethingUserRemote`
- Refactors Canada SSO to use concrete `DosomethingCanadaSsoUser` instead of common user
- Harmonizes input and output remote user data
- Provides minor code improvements to UK SSO

#### Testing
![image](https://cloud.githubusercontent.com/assets/672669/5323628/a16230a2-7cda-11e4-98b3-1f35f2f3fba6.png)