Use type tuple() instead of record()

Dialyzer doesn't recognize the type record(), so let's use tuple()
instead.
Merge pull request #149 from legoscia/record-type-specs

Use type tuple() instead of record()
Merge pull request #148 from legoscia/travis-fixes

Travis fix, unit test fixes
Add tutorial explaining how to run the LINC-Switch with the Mininet

The tutorial briefly explains how to install the Mininet with the LNIC and run
simple ping example using Mininet virtual network.
(Motivated by #129).
Merge pull request #150 from FlowForwarding/issue129

Add tutorial explaining how to run the LINC-Switch with the Mininet
Use eunit test objects in linc_us4_packet_tests

With this change, we can run every single test case even if earlier test
cases fail, thus letting us pinpoint exactly which edit actions have
problems.