[46804595] show nav-links horizontally in dashboard

Make nav-link prettier by activating bootstrap's element selection and styling.

Also a some code-refine to remove redundant params for _form.html.slim.

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge branch 'master' of github.com:vmw-tmpst/heroapp-LetsHire into JobDescription2

Conflicts:
	app/views/layouts/application.html.slim

Signed-off-by: Henry Chen <hchen@vmware.com>
[46357891] edit interview
Merge master code
Merge pull request #39 from Henry-CF/JobDescription2

[46804595] show nav-links horizontally in dashboard
Merge pull request #40 from easeway/interviews

[46357891] edit interview
Merge remote-tracking branch 'vmw-tmpst/master' into filter_for_controller

Conflicts:
	app/controllers/interview_controller.rb
	app/views/layouts/application.html.slim
	spec/controllers/interview_controller_spec.rb