API Injector supports nesting
BUG Resolve issue with DirectorTest breaking RequestProcessor
Injector::nest and Injector::unnest are introduced to better support sandboxing of testings.
Injector and Config ::nest and ::unnest support chaining
Test cases for both Injector::nest and Config::nest
Merge pull request #3058 from tractorcow/pulls/injector-stack-tests

API Injector supports nesting