[API] add IntelliJ Saros class

Change-Id: I301153f141f8d52b2d4af2d8c0b278fd0fa9791d
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1797
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>
Reviewed-by: Holger Schmeisky <google@schmeisky.com>