Make sure the tabular results are clear and colorful

[davidedelvento]

• include table headers
• colorize lines according to activity type (e.g. rest/recovery in green, warmup/cooldown in blue, running with a target in red, etc)
• use the same color coding (or other visual cues) everywhere, e.g.
  • when creating the json for the intervals
  • when actually running
  • when reviewing the history of the run in tabular format
  • when reviewing the history of the run in map
  • when reviewing the history of the run in the graph (chart)
  • probably somewhere else

I'm actually working on graph (chart), see a initial mockup at https://github.com/PhilJay/MPAndroidChart/issues/3339 (I plan to share the code for this with you soon)

See https://github.com/davidedelvento/runnerup/issues/7