1071960 - Support message authentication.

Support message authentication.

There is a good deal of overlap in the areas of code impacted by adding support for message authentication, the story about reworking how agent related task timeouts worked and general porting to gofer 1.0.  In the interest of changing these code areas and associated unit tests, once, I just did the work all at once.  I will add comments to the PR to help reviewers understand the intent of each change and how it relates to these efforts. 

Don't freak out about the number of files changed.