Provide estimated row count as a lazy loaded value

[kasper]

Currently the AnalysisListener? interface defines a method like this:

public void rowProcessingBegin(AnalysisJob job, Table table, int estimatedRows);

The last parameter (the int) should be replaced by either a (lazy loaded) Ref<Integer> or preferably an interface for gathering more information about the job. This will benefit performance in two ways:

• The querying of the count can be done in parallel with the actual execution.
• Sometimes the count is actually not used at all (for example in the Command-Line Interface), and it's a shame to waste time retrieving it then!

[kasper]

Fixed as of rev. [3040], [3041], [3042] and [3043].