Problems:
1. Without a message, users don't find 'last'
2. Showing a message for every error clutters output.
This tries to address these issues by:
1. Only showing the message when other feedback has not been provided and
'last' would not usually be helpful. This will require ongoing tweaking.
For now, all commands except 'compile' display the message. 'update' could
omit the message as well, but perhaps knowing about 'last' might be
useful there.
2. Including the exact command to show the output:
last test:compile
and not just
last <task>
3. Highlighting the command in blue for visibility as an experiment.
Review by @ijuma and @retronym, please.
the custom scalac Reporter now delegates to an instance of
an sbt interface called xsbti.Reporter
handling compilation logging is now mainly done on the sbt-side of the
compiler interface
the xsbti.Reporter interface provides access to richer information
about errors and warnings, including source file, line, and offset
xsbti.Reporter can be implemented by users to get access to
detailed information without needing to parse the logging output
the CompileFailed exception that is thrown when compilation fails now
includes an array of the problems, providing detailed
error and warning information that can, for example, be consumed
by doing a mapFailure on 'compile' and using 'Compile.allProblems'
Eugene Vigdorchik
Mark Harrah