Revert "Tasks references upstream and downstream tasks using strings …

…instead of references"

This reverts commit 6c1207b.

Missing comma in setup.py

Missing comma in setup.py

v1.7.0

Merge pull request apache#1147 from r39132/master

Enhance CLI Test command to accept a JSON-formatted dictionary of par…

Merge pull request apache#1147 from r39132/master

Enhance CLI Test command to accept a JSON-formatted dictionary of par…

Hotfix configurable DAGBag Import timeout

Merge pull request apache#853 from airbnb/hotfix_getdag

Fixing a bug where some dags can't be retrived from DagBag.get_dag

Merge pull request apache#848 from airbnb/del_dags

Delete dags from dagbag

Only pickle_info for non subdags