Simplify dx find jobs --trees

Conflicts:
	src/python/dxpy/scripts/dx.py
New API methods findExecutions, findAnalyses
High-level wrappers for findExecutions
Begin dxclient integration of findExecutions
Begin fixes to rendering of analyses in pretty-printed output
dx find analyses is not compatible with --trees
Remove trees format and substitute with repeat call
Debugging improvements
Remove --summary argument (subset of fd5f8234 for merging)
Remove dxpy.find_executions(format=trees)
Begin tests
Tests
Remove debug printout
Fix analysis-job nesting
Alias --root to --root-execution
Add dxclient find executions tests

Conflicts:

	src/python/test/test_dxclient.py
Remove test dependency on authserver and fix job event wait logic
Render analysis names in CLI as underlined bold blue, not bold white
Remove dxpy test case dependency on authserver
Address issues raised in code review