added utils for switch cases with strings
Merge pull request #84 from datacratic/hash_table_switch

added utils for switch cases with strings
HttpClient: operator<< for HttpClientError now outputs the error string
use gettid from jml
ServiceProxyArguments does not provide ZooKeeper option anymore if not needed
updated jml
Merge branch 'master' into http-client-ih

Conflicts:
	service/http_client.cc