First implementation of "two line" formatting.
Messages have a title and optional content.
Distinguishing writing on "your talk page" from another talk page in messages.
Change-Id: I9051e4bfb66d1c25c1bf68ec092b52fd90544336
This version is very rough.
For an example set of Minimum Releasable Functionality, this version will notify users on
changes to their watchlists or to their user talk pages.
However, it is still missing a conversion script to turn watchlists into echo subscriptions.
For now, notifications can be viewed through the new special page Special:Notifications, or through the API module provided.
Change-Id: I5867226e3e6195fbed81f4b5803e2310f057ffc4
