Fixed issue with wrong validation of jobs creation

* It's possible to send an empty array to mains
* Added check to create Pig/Hive flows with binary in mains requirement

Fixes bug#1237434

Change-Id: Ia04d0fa642386bf5d05300b7013fe91cca6aada2
Add __init__.py file to enable edp validation tests

Unit tests for edp validation were not running because
the absence of __init__.py in the edp directory caused
edp to not be detected as a package by tox.

Change-Id: Ief2a1a1c230a32d2c2ed99b85cbd43f852b64f4e
Merge "Add __init__.py file to enable edp validation tests"
Merge "Fixed issue with wrong validation of jobs creation"