This better shows the semantic of the API. For already setted fields,
mergeFromString do replacement for singular fields and appending for
repeated fields.
The last up-integration from github to google3 was made at commit
e28286fa05 but somehow the change in
that commit is not actually in the up-integration CL and as a result
that change was reverted by the down-integration. Restoring them
should make the jenkins tests running again.
1. Added ruby22 and jruby tests to jenkins.
2. Added javascript tests to jenkins.
3. Added golang tests to jenkins.
4. Removed ruby19/ruby20 tests from travis. Support for ruby 2.0 has
ended since 2016/02/24.
https://www.ruby-lang.org/en/news/2016/02/24/support-plan-of-ruby-2-0-0-and-2-1/
Change-Id: Ie984b06772335352a4be7067ab2485f923875685