Merge branch 'master' into webplugin
Add logging to file; Make core options use PluginOption as well
Warn when one of the devices disappears; Try to obtain new devices on
next action
Add 'finish_capture' method to device API

chdkcamera switches to 'play' mode on finish_capture now
web: Stream workflow ZIP instead of going through a temporary file
web: Try to get thumbnails from EXIF data, fall back to scaling if
pyexiv2 not installed
web: Logging in 'persistence'
web: Poll for all changes in one request
web: Polling returns warning and error messages; Will be displayed in UI
Merge remote-tracking branch 'jb/webplugin' into webplugin