allow hacking to set dependencies

allow hacking to define flake8, pep8, pyflakes dependencies.
see Change-Id: Ie61a97d5ed26bb8cab04df686a4a2d1df9976f1d

Change-Id: I183dbc82bfbed0e10b75c1eb8f0f926105e3d319
Implements field validation for complex query functionality

Implements: blueprint complex-filter-expressions-in-api-queries
Change-Id: Id186995b4c7106f9e3ceb596b3faf46cb2231790
Merge "allow hacking to set dependencies"
Merge "Implements field validation for complex query functionality"