Close T199

Close T201

+ update default base_url

+ Improve docstrings and warnings

This permits to make sure the call takes place as expected.

Beware though that does not permit to check the values have not been
hard-coded...

Improve test readability and maintenance.

The setup needs some clarification though

<~=~> dependency injection

Still, we must enforce this before flask

Sample client:
```python
import requests
r = requests.post(
      'http://localhost:6543/api/1/uploadnsearch/',
      files={'file': open(filepath, 'rb')})
```

Sample output:

```ipython3
In [125]: r.content
Out[125]: b'{\n  "found": true,\n  "sha1": "da39a3ee5e6b4b0d3255bfef95601890afd80709"\n}'
```

Beware, write on server's side in temporary location which is cleaned up
after hash computation.

No limit is set on the upload either.
Need to make sure the limit is done on deployment part before deploying this

reference: http://getbootstrap.com/css/#forms

in particular: avoid that everything is contained in div.title

most notably:
- do not expect /about to *be* a specific string, but to contain it
- remove pointless redirection test

also include in the homepage a (hyperlinked) list of available entry
points