adomd xmla parameters support

parser will interpret @P as ParamRef("P") and xmla parameters are added
to lookup
datatype support still very limited, more tests needed
CHILDREN_CARDINALITY adomd executeCellSet performance issue

mondrian.olap.FetchChildrenCardinality=false will return child level
cardinality instead
 when count is required and children not in cache don't materialize list
of children
unused var
Merge pull request #7 from tgf/evergreen

children_cardinality and @parameters