Show error description in live-view panes

Signed-off-by: Ismael Luceno <ismael.luceno@corp.bluecherry.net>

Closes: https://github.com/bluecherrydvr/bluecherry-client/issues/117
Keep playback speed constant when changing videos

Signed-off-by: Ismael Luceno <ismael.luceno@corp.bluecherry.net>

Closes: https://github.com/bluecherrydvr/bluecherry-client/issues/90
Fix layout cell size calculation, don't add extra width and height

Signed-off-by: Ismael Luceno <ismael.luceno@corp.bluecherry.net>

Closes: https://github.com/bluecherrydvr/bluecherry-client/issues/192