Update README.md

config.ini => config.yaml
Bugfix: added getter for interval attribute on TimedTimelapse, went missing since a refactoring a couple of weeks back.
Title and limited color control via settings
Merge remote-tracking branch 'origin/master' into devel
Merge branch 'richard-jm/appearance' into devel
Fixed some whitespace and reworked custom title to always include an "OctoPrint" prefix (gotta protect the "brand" here ;))