disallow failures for builds in Travis CI

version bump to 0.4.0

Merge pull request sysrepo#199 from rastislavszabo/notifications

Documentation updates

Merge pull request sysrepo#130 from rastislavszabo/master

version bump to 0.2.0

Merge pull request sysrepo#38 from rastislavszabo/master

version bump to 0.1.0