Revision 631455

Improve phase-tracking, event dispatching, and align build headers as events dispatched to the default event monitor...also, add debug-level enter/exit phase output in the default event monitor. Finally, refactored code that actually renders the build plan and executes the mojos for each task-segment in the lifecycle executor, to eliminate all the duplication.

This lays the ground work for improving cache management, since I also added event types for embedder control (keep in mind that event monitors can be used to control when the project/model cache is flushed, for example).