Output multiline doc comments over multiple lines

Tested: on Linux

Bug: 15779934
Change-Id: I6f822f1705e443d8721ea208dcb021aad3c8715c
Fixed bug in convenient constructors for Java/C#

Also fixed Go unit tests not being up to date with recent schema
changes.

Change-Id: I42e619f9c5ea05f6f937c68a5c8a92462c46bce3
Tested: on Linux and Windows.