Add network migration modules
Set unix fileformat for test_user
Introduce Context
Extends test_user scripts to validate flow a bit
Remove tralling white spaces
Add ability to choose plugins for migration_disk
Implement context
Add tests for server tasks
Replace src, dst with context in tests for floating ip, secgroup
Modifies test_tenant to validate flow filling better
Updates test_role to validate flow creation
Updates test_flavor to verify flow tasks adding
Moves tenant migrate event before flow building
Add tests for server migration flow
Test for restore floating ip flow factory
Test construction of flow for secgroup migration
Test construction of flow for floating ip migration
Test construction of flow for snapshot migration
Fix problem with expired token during clouds reset

Fixes bug #PH-163. The logic of the check of clients moved to clouds
extension.
Revert cirros download URL change