updates for test-framework akka 2.2.1, swap to gatling snapshot, some helpers for developing
Merge pull request #3 from dmakhno/gatling-snapshot-akka-221

Updates for test-framework akka 2.2.1, swap to gatling snapshot. UUID reintegrated (was needed in Gatling 1.x, not in 2.x pre-stages, backported latelly (https://github.com/excilys/gatling/commit/d88aaa36a50727c3b89de7b14fb11d1a0b9ef929#L1R47). Runner has to be more generic/reusable in the gatling lib...