Clean-up of the HTML templates.
Separated the list of stenograms into numerous pages.
Merge branch 'microdata1'

Conflicts:
	create_html_pages.py
More microdata.
Cleanup of html.
More HTML and template cleanup/refactoring.
Add a layer to the nav bar (more compact now).
Save and show the original url of the data.
Add microdata to the registration and votes pages.
Unsuccessful attempt at creating a nice graph of votes.

The formula for the weight was

`agreements(yes or no)/common presences`

and it was clipped for

`common presences < average common presences`

where `average common presences` is calculated from `p_vote` and `p_abstain`
assuming complete independence of the votes.

`average common presences = all session * p_vote**2`

The results were not nice:

 - only GERB got non zero vertices. This means that the metric favors those
   with more presences (the other parlamentary groups are frequently absent
   from the sessions).
Better graph of votes.

Clipping the data by median instead of mean works well.
Small fix to the microdata.
Reenable all subroutines in create_html_pages.
Make it possible to add stenograms without starting over.