The test cases allocated servers in a way that doesn't comfortably suit
the way the servers are now allocated. Adding a helper C++ class to load
module defaults makes it easier to do explicit server initialization in
tests.
The binlogrouter was also fixed in this commit as it uses servers much
like a test would use.
The same mechanism that is used for modules can be used for the
configuration of the core objects. This removes the need for the redundant
code that validates various values that is already present in the code
that modules use.
To prepare the router's for the eventual removal of the router_options
parameter, the API option arguments should not be used. The parameters can
be substituted by tokenizing the value of the parameter that is still
stored as a part of the service.
