New manual sections get default change note

"New section added."

Pairing with: @themitchell
Refactor some wiring gunk into ManualDocumentBuilder

+@themitchell
Merge pull request #128 from alphagov/initial-change-note

New manual sections get default change note
Version bump govspeak to 1.6.1

1.6.1 fixes parsing errors for $LegislativeList and $PriorityList when
they don't follow an empty newline.

Fixes
https://trello.com/c/hel31WzU/159-bug-html-for-legislative-list-appears-on-page
Merge pull request #130 from alphagov/bump-govspeak-to-1.6.1

Version bump govspeak to 1.6.1
Add missing require for ManualDocumentBuilder
Merge pull request #131 from alphagov/require-manual-document-builder

Add missing require for ManualDocumentBuilder
Bump Govspeak to fix LegislativeLists

When passing content through the App, \n\n is being turned into \r\n\r\n
which breaks the $LegislativeList parsing. This version of Govspeak
parses this correctly.
Copy CMA case metadata into extra_fields

The code was updated to pull the CMA case specific metadata from
extra_fields but the data wasn't migrated.
Merge pull request #133 from alphagov/bump-govspeak-to-fix-legislative-lists

Bump Govspeak to fix LegislativeLists
Merge pull request #134 from alphagov/fix-cma-metadata-for-new-drafts

Copy CMA case metadata into extra_fields