port SoftwareProcess so it supports hierarchical tasks, and inspection of individual ssh commands
fix a cross-execution-context bug, and make logging/warnings much less verbose and more informative
attach "stream" tags to tasks (in BrooklynTasks), and update ScriptHelper and SshTask to use this
adds task streams to the REST API and to the GUI; also tidies up misc elements of GUI (including clicking on a task takes you directly to drill-down (no inline summary), and blocking details for tasks in details top section)
some cleanups, mainly for the GUI (compress tasks by default, and ensure DST blocks on tasks sequentially so blocking link in GUI is more useful)