refactor server tasks and related models to be more testing conducive.
Improve quality of tests and fix various bugs along the way.
WIP server + proxy tests (TOO TIRED)
invoke superConstructor from prototype
label mergeTree’s to help identify bottle necks
config can now be extracted from the project project
commandOption help is a factory.

cleanup tests accordingly
Merge pull request #776 from stefanpenner/cleanup

WIP - Testability/Quality of Server/Watcher/Builder/Proxy
Specify descriptions for trees.
keep output in is own describe block
Merge branch 'cleanup'
Merge pull request #863 from rjackson/update-descriptions-for-trees

Specify descriptions for trees.
Allow concurrent `ember test --server` and `ember server`.

Prior to this, both `ember server` and `ember test --server` attempted
to write to (and clear) `tmp/output`. This allows the test task to use a
custom randomly named temp dir instead (which prevents the collision).