Youtube handle support

Features

• You can now add channels by their youtube handle e.g. @lolesports, this is the new default for youtube #78

Fixes

• Fix lookups for twitch vods in vod viewer to use the display name/login name instead of the id #82

Misc Changes

• livestreams.json display names will be automatically updated for twitch channels
• Reduced number of calls to youtube api when looking up videos
• Better error messages when failing to open chat for a stream, including the command that attempted to be executed
• Fixed an initialization bug where authentication sometimes wasn't requested when adding your first twitch stream to the
• Youtube channels will display as their handle from now on if they were added via their handle