Changed the colors of the Deep-/Light Sleep and Activity datasets.
* Deep sleep has been used as basic color,
* Light sleep is a color that is monochromatically analogous
* Activity is a color triadic to the basic one
- supports zooming an panning
- displays labels for all x-values (= time of day)
- fix deep vs. light sleep constants
- increase activity data buffer size for Mi Band
For a start, use android-logger as backend. Needs a better configuration
but no time right now.
For file-logging we will use logback as slf4j-implementation.
