First public release of switchboard.

Most of the work for this release was on the client/worker interfaces, and documentation.

• Implemented getMailboxes, getMessageList, and getMessages JMAP commands.
• Added watch commands.
• Added worker interface wrapping the client interface.
• Added project site, built using jekyll and hosted by GitHub pages.
• Added javascript example client.
• Updated release build process.

Thanks to @ltavazzani, @bismark, @mickhagen, @kunks001, @traviagio, @RRotesi, and Carlos Lagrange for putting putting this together.