autoscale module: fix launch_config.user_data creation via connection

backward-compatible support for Python 3.3+
Use literal binary syntax
Enable and fix Autoscale unit tests by default
Merge branch 'nishigori-b64encode-launch-config-user-data' into develop

Fix an error in Python 3 when creating launch configs. Enables AutoScaling
unit tests to run by default. Fixes #2591.