Add meta_description to pages
Merge pull request #9 from moneyadviceservice/meta-description

Add meta_description to pages
Remove parent_id from page#edit
Add config and constants dependencies to tests. Fixes failing tests
Fixes bug where clicking mode switch button triggers conversion
Add test for thrown error
Set mode from config
Use constants in place of hardcoded strings
Remove H1 button

Article Title is set via a separate field.
Use a single toolbar for both editors
Add some comments
Add active state to mode switch buttons when selected
Add eventsWithPromises
Improve language of some tests
Add TODO for new test
Add .jshintrc
Remove unused events param
Use strict mode on mss-editor
Update bindEvents method name
Use strict mode on app