- moved createRequestMessage() into unittest_utils
- added more bogus-address tests in asiolink unit test
- added tests with IPv4-mapped IPv6 addresses, but disabled because
  v4-mapped addresses don't work on my test systems 
- added documentation for asiolink test helper functions
- moved MockSession, MockServer, etc from auth/recurse unit tests
  into a single external mockups.h to reduce code duplication


git-svn-id: svn://bind10.isc.org/svn/bind10/branches/trac327@3264 e5f2f494-b856-4b98-b285-d166d9295462