[CODE] improved bulk_insert rows management
[OPTI] ngrams extraction is treated little by little

(yeeehhhah!)

[CODE] removed unused imports

(documents are parsed from resources, but ngrams are not extracted yet)

 - immediate
 - threaded
 - managed with Celery
(see `gargantext.util.schedule`)

[FEAT] added some file managers (save, upload, download)
[FEAT] added Celery workers
[CODE] planned an interface for PubMed scrapping, see `gargantext.util.scrapping.pubmed`
[DOC] added a README and a TODO

see hardcoded constans in `gargantext/constants.py`
(also, kept working on the single project page)

[CODE] more cleaning (espacially in the views)

(using `scoped_session`, removed unnecessary use of Aldjemy)

(6952a98f)

applied proper indentation and nesting

[FEAT] url '/projects/' is available

Restart from scratch; a few static pages are available