Risk

- Calculates the applicant(s) risk percentage and level
- Refactors Affordability calculations as per the regression test formulas
- Refactors Affordability JS unit tests
- Set up dynamic slider for lifestyle spend input (20% - 200%)
- Refactor slider directive to dynamically set percentages for minimum and maximum range
- Refactor all directives to follow our JS styleguide/conventions.

@benbarnett @gjvis @asmega