CVS Check-in: Couple bugs were fixed in subquery handling

1. Prepared statements were failing if parameters were in subquery
2. In some cases subquery with UNION were not handled properly

Files:

Checking in src/com/edb/gridsql/parser/handler/WhereClauseHandler.java;
/cvsroot/gridsql/apps/gridsql/src/com/edb/gridsql/parser/handler/WhereClauseHandler.java,v <-- WhereClauseHandler.java
new revision: 1.5; previous revision: 1.4
done
Checking in src/com/edb/gridsql/optimizer/AttributeColumn.java;
/cvsroot/gridsql/apps/gridsql/src/com/edb/gridsql/optimizer/AttributeColumn.java,v <-- AttributeColumn.java
new revision: 1.3; previous revision: 1.2
done
Checking in src/com/edb/gridsql/planner/QueryPlan.java;
/cvsroot/gridsql/apps/gridsql/src/com/edb/gridsql/planner/QueryPlan.java,v <-- QueryPlan.java
new revision: 1.16; previous revision: 1.15
done
Checking in src/com/edb/gridsql/planner/QueryPlan.java;
/cvsroot/gridsql/apps/gridsql/src/com/edb/gridsql/planner/QueryPlan.java,v <-- QueryPlan.java
new revision: 1.17; previous revision: 1.16
done
Checking in src/com/edb/gridsql/planner/Leaf.java;
/cvsroot/gridsql/apps/gridsql/src/com/edb/gridsql/planner/Leaf.java,v <-- Leaf.java
new revision: 1.7; previous revision: 1.6
done