Use log labels which all have the same width (#1165)
Use log labels which all have the same width (#1165)

Closes #1153

Since `SEVERE` doesn't have a nice way to shorten it we'll pad
everything to 6 characters.

- Don't use the labels or levels coming from the logging package, bucket
  things into 4 levels which are more sensible.
- Add a different color for `FINE` logs.
dart-lang/build,dart-lang/build,dart-lang/build,dart-lang/build