added override for node detection

Summary: for certain silly networks (azure) we need to be able to specify a hostname/ip for node detection.

Test Plan: eyes

Reviewers: carlos, neil.dahlke

Differential Revision: http://grizzly.memsql.com/D4333
print version number at startup

Summary: --

Test Plan: --

Reviewers: carlos, neil.dahlke

Differential Revision: http://grizzly.memsql.com/D4334