Merge dev back to master for release.

[eap]

This Pull includes a batch of dsub improvements and bugfixes.

Bug fixes:

• ddel validates provider-specific arguments (see bug ddel gives stacktrace when omitting --project argument #87)

Internal improvements:

• Improved use of the --age flag allowing some tests to run faster.
• Refactored local provider to pull out runner.sh.

[eap]

All tests pass -

Test timing summary:

28	e2e_logging_paths.sh (local)
31	e2e_logging_paths_tasks.sh (local)
34	e2e_ddel_tasks.sh (local)
34	e2e_logging_paths.sh (google)
36	e2e_dstat.sh (local)
39	e2e_dstat_tasks.sh (local)
39	e2e_logging_paths_tasks.sh (google)
40	e2e_labels.sh (local)
41	e2e_dstat.sh (google)
43	e2e_dstat_tasks.sh (google)
50	e2e_ddel.sh (local)
54	e2e_ddel_tasks.sh (google)
104	e2e_env_list.py (google)
105	e2e_command_flag.sh (google)
105	e2e_error.sh (google)
106	e2e_env_list.sh (google)
115	e2e_python.sh (google)
117	e2e_env.sh (google)
117	e2e_input_wildcards.sh (google)
118	e2e_io_auto.sh (google)
120	e2e_io.sh (google)
122	e2e_io_tasks.py (google)
125	e2e_io_gcs_tasks.sh (google)
125	e2e_io_tasks.sh (google)
161	e2e_non_root.sh (google)
170	e2e_io_recursive.sh (google)
178	e2e_ddel.sh (google)
180	e2e_labels.sh (google)
187	e2e_after_fail.py (google)
198	e2e_after.py (google)
261	e2e_env_list.py (local)
283	e2e_error.sh (local)
285	e2e_command_flag.sh (local)
294	e2e_env_list.sh (local)
295	e2e_local_recursive.local.sh (local)
296	e2e_input_wildcards.sh (local)
297	e2e_io_recursive.sh (local)
297	e2e_io.sh (local)
303	e2e_python.sh (local)
304	e2e_env.sh (local)
304	e2e_local_relative_paths.local.sh (local)
305	e2e_io_tasks.sh (local)
306	e2e_io_auto.sh (local)
316	e2e_io_gcs_tasks.sh (local)
319	e2e_io_tasks.py (local)
326	e2e_non_root.sh (local)
335	e2e_after.sh (local)
342	e2e_after.py (local)
343	e2e_after_fail.sh (local)
344	e2e_cleanup.local.sh (local)
350	e2e_after_fail.py (local)
389	e2e_after.sh (google)
408	e2e_after_fail.sh (google)

[mbookman]

LGTM