Andreas Jaeger 60acb5cfbb Avoid
Instead of using, we can install horizon now directly from pypi
- or use the current branch in CI system using tox-siblings.

Update tox.ini for this change and add horizon to requirements file.
Use new location for constraints file.

Change-Id: Iabdad92e19b57b82ced7ae20043a08d174995305
2019-06-05 08:10:14 +02:00
tox_install.sh_ORIG start 2018-05-07 19:08:38 +02:00