Revert "Revert Travis CI introduction"

Trying again.
Bump libzmq version
Tests are now executed using `make`

This makes it possible ot also incorporate `go build` as a test.
Installing go packages before tests
README: Spelling mistake
Use Travis CI

Finally got it working after migrating to ZeroMQ version 3(.2).

Merge branch 'travis-ci' into develop

* travis-ci:
  README: Spelling mistake
  Installing go packages before tests
  Tests are now executed using `make`
  Bump libzmq version
  Revert "Revert Travis CI introduction"