Created function to send texts to pypln
Merge branch 'master' of https://github.com/NAMD/mediacloud_backend

Conflicts:
	capture/downloader.py
Renamed pypln to nlp
Created a function that send texts to pypln.
Merge branch 'master' into feature/send_to_pypln

Conflicts:
	capture/downloader.py
Merge branch 'master' into feature/send_to_pypln
Started updating nlp module to use PyPLN API
Merge branch 'master' into feature/send_to_pypln

Conflicts:
	requirements.txt
started to add tests for nlp module
added a first test of pypln documento insertion.
created script to load articles into PyPLN
Merge branch 'master' into feature/send_to_pypln
incomplete
import working but still needs improvement
improved adding documents in batch.
fixed a problem
Removes the responsability of sending to pypln from the downloader

As far as I recall, we agreed that it would be better to have another cronjob
to upload files to pypln, instead of making it part of the download process.
Simplifies the code in `send_to_pypln`

Since `pypln.api.Corpus.add_documents` just calls
pypln.api.Corpus.add_document` multiple times
(https://github.com/NAMD/pypln.api/blob/develop/pypln/api.py#L187) this patch
reduces code duplication without including extra complexity.
Fixes bug in send_to_pypln

The `pypln.api.Document` object returned when inserting it in pypln does not
have in `_id` key. I tried to clarify the names of the variables to improve
readability.
Removes `print` statement from `nlp.send_to_pypln`

The idea is to use the `nlp` module as a library, so it shouldn't send data to
stdout.