Roadmap 0.2.0

#### Todos
- [x] Fix bug with `expand` prompt in Terminal.app
- [x] Fix bug with `checkbox` on Linux
- [x] Fix #30
- [ ] Check #25 (not sure if fix will hit 0.2.0)
- [x] Close #14
- [x] Decide what are officially supported prompt and environments
- [x] Test different environments (And maybe get a tester resources list)

#### Change log
- New prompts: `expand`, `checkbox` and `password`
- Unicode char now used for Mac and Linux env
- `choices` array can now be a function to allow filtering available choices depending on previous answers
- Tests refactoring for easier maintainability