Tests and bugfixes

Added tests for replica set configuration (disabled on travis-ci).
Added a test for fetching an expired session.
Better `make test-cov` rule.

Change-Id: I8830d3d22a2bf951785a3d31d53dd417ef8f0ab3
Docs, tests

Corrected documentation.
Added a test for `expireAfter` property.

Change-Id: I0f89809f0c8afa3cad2f5b59e39d993d469ad071
Merge branch 'feature/more-tests' into develop
v0.0.5

Change-Id: I3082945adf9be5472977c6e359934405819564d3
Merge branch 'release/0.0.4' into develop