More work on commands, statemgmt, EL references

More work on commands, statemgmt, EL references

Attempts to make state management still more transparent to
the logic of setting command parameters - basically in order
to allow command parameter settings to get arbitrarily complex
without having to worry more than necessary about state handling

Extracts commands to a separate class for EL access (from pages) -
Can thus be referenced like, say, req.search.query for setting the query
parameter of the search command. Attempts to reduce the number of
methods on the pz2 object, which was gradually becoming less
manageable.

Creates a dedicated class for each pazpar2 command for type-safe
setting of parameters and to manage complexity.

Fixes missing faces-config.xml (might have caused the CDI
framework to NOT scan the pz2utils4jsf jar for all annotations).

Uses listener pattern to alert the session object about state
changes.