First attempt to import 'betänkanden'

Added Committee(Group), Document, and CommitteeReport(Document) to
db_structure. Have also started to try it out in populate_orm.py
Merge branch 'develop' into import_betankanden
Merge branch 'develop' into import_betankanden
Added report points to ORM structure

Created CommitteeReportPoint, representing 'utskottsförslag'. The added
AcclaimedPoint and PolledPoint as subclasses to represent points where
decision was taken by acclamation or vote.

Some uncertainties remain:
 - How to characterize the proposal? Can be as simple as 'Riksdagen avslår
   motion', but can also be all sorts of weird formulations.
 - Locate the winning proposal (mostly 'utskottet' wins, but sometimes
   'reservation 3')
 - Relate this information to 'motioner'
Inserting points in 'betänkanden'

Use 'rm' and 'beteckning' to identify reports and 'votering_id' to find
poll.

Also fixed small bug in naming in db_structure.py
Now using PolledPoint instead of Poll

PolledPoint:
 - Now meant to have connection to CommitteeReport (betänkande) and to
   votes to enable analysis connecting votes to committees (utskott)
 - Adds title from 'utskottsforslag' if available (does not add anything
   on the committee's recommendation yet)
Merge branch 'import_betankanden' into develop