Without sudo travis is executing build tasks using docker and waiting
time in this case is really small, usually not longer then 10 seconds.
postgresql-9.5 is installed via addons.apt.packages (without sudo)
But ports 5432 and 5433 are busy. So I had to ajust environment.py to
assign port from higher diapason.
And a few words about build tasks:
First task is used for executing unit tests for all different python versions
The second one is used for executing acceptance tests against etcd
The third one is used for executing acceptance tests against zookeeper
acceptance tests are executed with python2.7 and python3.5
In addition that I've introduced caching of python virtual environment.
It really helps to reduce time needed to install python modules.
