check in sixense not Sixense
don't look for debug sixense on UNIX to avoid missing symbol
exclude sixense debug on UNIX only, not APPLE
Merge pull request #3205 from birarda/select-library

lowercase the SIXENSE_ROOT_DIR
Merge branch 'master' of https://github.com/highfidelity/hifi into domain-server-auth
don't flip order on node socket, HifiSockAddr is handling
persist and recall domain-server web sessions from ini settings