Auto types aren't very neat as return values because they move the burden
of knowledge to the reader. Using an explicit, and somewhat
self-explanatory, type makes it easier to assess the code without knowing
the implementation of the type.
Added some helper functions into the MaxScale class and default parameters
into the connection creation functions. Also made the ip() function const
correct.
Combined functions into one which only used different default
values. Removed unused functions. Used std::string where possible to make
their usage easier. Hid code that isn't used externally.
The ssh_node function now supports printf style arguments. This is used to
simplify command execution on the nodes.
Curreltny, in addition to its old usage, it is used to drop extra
databases when replication is started.
