HTML5/D3: Cloud authentication (#175 #177)

Also changed ‘bootable’ code references to ‘cloud’ in login.js.
HTML5/D3: Permeate display units
tuesday night edits!

- robustness in steward on startup
- NEW: media/audio driver for UPnP (rocki)
- prepare for adding telldus-live support
- HTML5/D3: fix duration calculation
UPNP audio driver: minor fixes
have sonos/upnp expand parameter for playback URL
typo
provisional plantlink support
remove plantlink debug
HTML5/D3: Login button fix.