Adding dart2dart task option
tweaks
Adding a CompilerTargetType enum
better logic on file name generation
much better tests
Merge branch 'pull_13'
fix error message for duplicate files
pub: bumped min bot_io version to 0.20.2
test bot_io: removed prints
hop_tasks: removed enable-type-checks flag

Thanks, Kathy
https://plus.google.com/105904968710974272643/posts/BnHt67xKyKL
hop_tasks: toto in unit_test
tool/hop_runner: fixed analyze_test_libs
test/hop: nits to runTaskInTestRunner
hop: renamed _SubTaskContext to _TaskContext
hop: task registration methods return the registered task

...is nice
hop: _LoggerParent/_LoggerChild fun...