Merge changes Iacd2f028,I43a6d573,Ibb6c93bb

* changes:
  Secure Key Management
  Improved integration tests
  [WIP] Multi-vdu, multi-charm support

diff --combined Makefile
index c63a6ba,51e19b4..abc2c39
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -2,12 -2,10 +2,12 @@@ clean
        find . -name __pycache__ -type d -exec rm -r {} +
        find . -name *.pyc -delete
        rm -rf .tox
-       rm -rf tests/charms/tmp*
+       rm -rf tests/charms/builds/*
  .tox:
        tox -r --notest
  test: lint
        tox
  lint:
        tox -e lint
 +package:
 +      python3 setup.py --command-packages=stdeb.command bdist_deb