Creating duplicate connections using the Backend class allows the
connections and their handling to be tested at the same time that the old
system is in place. This should make it somewhat easier to grasp what
changes and where when the new implementation is taken into use.
The session commands are now duplicated as SessionCommand objects This
allows for an easier migration from the old session command implementation
to the new one.
Reorganized the main source file of readwritesplit. The internal functions
are first followed by the API entry points. The actual module definition
is the last declared object in the file.
The temporary table detection and handling now uses C++ containers to
store the set of temporary tables. The detection also uses the new query
classifier field info API to detect which tables and databases are
targeted.
