Add Bill URL for Divisions and Speeches

Bill subdebates include a unique ID that is used by ParlInfo to
tie speeches, the bill text and the bill digest together on a single
page which has a permanent URL. This patch adds this URL as an
attribute to speech major headings (which contain the Bill name used
for Public Whip) and divisions.
Seperate bill_id from bill_url attribute
Attach bill ids/urls to minor headings not major headings

Minor headings are where the bill names are now and into the future.
Keep subdebate.text where it contains bill information
Extract bill id/url information from subdebate.text where available
Fix order of url/bill_url when creating headings
Merge pull request #9 from maxious/add_bill_url

Add Bill URL for Divisions and Speeches