Create Bramble modules

bramble-android: plugins and any backend code needed for running bramble-core on Android
bramble-api: API for bramble-core
bramble-core: crypto, data, db, event, identity, keyagreement, lifecycle, plugins, properties, reliability, reporting, settings, socks, sync, system, transport, util (excluding HtmlUtils)
bramble-j2se: plugins and any backend code needed for running bramble-core on J2SE (everything in briar-desktop, by the look of it)