Lucyw/empty version

My colleague noticed that if you gem install with options but don't include a version, it is still run with -v, which when passed an empty string will error out (because empty strings in ruby return true).  All I did was added an "if version.length > 0" to the gem install process (the if...else was already in place), and a test to make sure that it still worked.  Let me know if anything else needs to be modified!