Clean the codebase

[roll]

Overview

After MVP we need to clean our codebase a little bit removing not used parts etc

Tasks

• [x] remove result_backend if it's not needed by chains - http://docs.celeryproject.org/en/latest/userguide/canvas.html - this one is imporants because it leads to additonal load
• [x] remove examples?
• [x] remove commands?
• [x] remove tox.ini?
• [x] remove setup.cfg?
• [x] remove goodtablesio.VERSION?
• [x] update readme
• [x] improve naming (helpers etc)?
• [x] signals to separate module?
• [x] better approach than global tasks_db?
• [x] import consistency
• [x] docstrings
• [ ] decide between having setup.py OR requirements.dev.txt
• [x] ~~merge concepts of validation_conf and job_conf to jobconf (raw as goodtables.yml)?~~
• [x] ~~tests to root?~~
• [ ] codestyle
• [ ] remove functions wrapping sqlalchemy models (user, job) (?)
• [ ] review TODOs
• [x] rename goodtables.io to backend? (MOVED #158)
• [x] fix coverage (back + front) (MOVED #165)
• [x] remove Procfile, runtime.txt
• [ ] rename validation_conf to inspection_conf (also task validate -> inspect) - it's how goodtables-py names it (less confusion) + no conflict with json schema validation (?)
• [ ] review how we use celery!!! there is some weak points like non atomic write to db/task run, potential hanging etc (checks with @roll)
• [ ] clean public dir before frontend building
• [ ] use jquery.js via npm?
• [ ] use bootstrap.js via npm?
• [ ] review contents of the bundle.js (if needed - bootstrap and styles is inside so the reason of big size)
• [ ] be consistent with github naming. I suppose it should be github/repo/<owner>/<repo> (we use org instead of repo in some places which is not correct)
• [ ] why we use success/failure instead valid/invalidacross codebase, database and UI - it doesn not seem really correct
• [ ] we should properly process first github hook request after activation (it has dummy payload but in GitHub UI it's shown as a hook failure) - we have just ignore it and return 200
• [ ] should we catch expected error inside validation tasks to do not have failed task in http://flower.goodtables.io/tasks?
• [ ] job.source_id should be NOT NULL

[pwalsh]

For now, putting this in beta, not alpha. It is too early to have a dedicated refactoring tasks IMHO. Of course, some of these could get picked up while doing other tasks.

[roll]

@pwalsh All of them are pretty minor. Renaming, deleting unused things, moving functions etc. No coding here. Like a few hours of work for the whole task.

Still recommend to do it as soon as possible (when @amercader will be having time for it) because some messy parts of codebase are slowing down the development.

[pwalsh]

@amercader I'm not to fussed about this for Beta, but I assume you and @roll just fix what comes up as you touch parts, so leaving it here of course with assignment to each of you.

[roll]

@amercader We could finish it straight after the Beta release. There are many minor things.