Build System: upgraded SDK dependencies

Previous commit missed AppEngine API, SleepyCat and Voldemort.
HTTP Library: upgraded Jetty 8 to 9

Removed requestBufferSize configuration property as Jetty 9 do not expose it anymore.
Tests: upgraded HttpClient from 4.1.3 to 4.2.2

Everything work as expected, was a previous 4.2.x that caused HTTP basic auth to fail.