Add new icons for tasks
Being able to display logs per tasks
Move non-direct tasks related events to sbt/events
On new log, append to rather than recreate tasks.logs

This avoids n-squared complexity.
code style fixes
code style fixes
Being able to display logs per tasks
Fix valueChanged handler
Change wording
Merge pull request #771 from typesafehub/wip/tasks-ui-experiment

Better task list in build