Merge tag 'sparks-2.9.5' into develop

2.9.5
one-liner fixes.
remove never-reached code.
OMG: implement http://www.12factor.net/config :-D
Use apt-get and dpkg in super-silent+non-interactive mode.
Push further the http://12factor.net/config with the `SPARKS_PG_*` variables.
variable name fix.
bump version in __init__.py
Merge branch 'release/3.0'