refactor(job): use EventEmitter for Job function
feature(job): use Kimono for the dividend calendar

Using Kimono simplifies the logic for retrieving the dividend calendar.
The API will always be update for the next 5 days.

Closes #21.
refactor(model): use Stock instead of Dividend
refactor(server): simplify server logic

Using Kimono there is less need to do server-side logic.
chore(repo): add mongodb service to Travis CI
refactor(server): clean requires
test(job): reset test cases for refactor
Merge pull request #22 from davidcaseria/job-refactor

Job refactor