Merge lp://staging/~chad.smith/lp2kanban/branch-to-card into lp://staging/lp2kanban

Add initial support for branch cards and taskboards. This branch only handles syncing and moving branch "MP/blue" cards on the Landscape 2016 board.

 Support was added for branch cards inside bugs2card because a lot of the logic is common and can hopefully be consolidated in a subsequent branch.

There will be a followup branch with added logic in bugs2cards to call moveToTaskBoard for feature cards that are manually dragged to the "$Group::Landed" lane.

src/lp2kanban/kanban.py:
- Define initial LeankitTaskBoard class
- Add optional CurrentTaskBoardId property to LeankitCard
- Add LeankitCard.moveToTaskBoard method to move a card as a subtask of another card
- Since Taskboard API calls live on a different route, rework API routes defined on the LeankitConnector class

src/lp2kanban/bugs2cards.py:
- _get_mp_info to handle non-bug branch records when parsing linked MPs
- should_sync_card to return true if external_system_url is a branch
- get_card_status returns proper status for cards that have external_system_urls linked but no bugs (external_system_id) linked
- add a loop to sync_board function which processes all "branch cards" through board.getCardsWithExternalLinks(only_branches=True)

config/sync.ini:
  - comment out [Landscape Cisco] board definition (as that should live in this board now

To test:
buildout
./bin/test
# to test against the new landscape 2016 board
./create_creds.py (this will create your creds to modify the shared 2016 board)
Select "Change anything" button in your browser to allow updating cards
make config
./bin/py src/lp2kanban/bugs2cards.py -c configs/sync.ini -b 'Landscape 2016'

# Tweak branches or drag cards at https://canonical.leankit.com/Boards/View/102392996#workflow-view that you want to see automatically moved back to the proper lanes.

What's lacking:
 unit tests to cover bugs2card sync_board (coming in a followup branch)