Remove dead code: mode setting
s/reportBuffer/reporter
simplify trytwice

tests pass
cleanup ContextReporter hierarchy (+3 squashed commits)
Squashed commits:
[2e23bb7] comment

tests pass: https://scala-webapps.epfl.ch/jenkins/job/scala-checkin-manual/1288/consoleFull
[fd069dc] just return unit
[1ada008] wip: refactor
immediacy