Job history

* add job_history model, change company_id type to uuid in invoices table, remove schema.rb
* create job_history automatically
* use job_histories in company_usage
Merge pull request #34 from vexor/durations_to_jobs

Durations to jobs
make UI fixes

* fix menu item titles for Linded Accounts and Edit Profile
* add appConfirmClick directive and use it for destroying user