drill

9f54aac3 - DRILL-3735: For partition pruning divide up the partition lists into sublists of 64K each and iterate over each sublist.

DRILL-3735: For partition pruning divide up the partition lists into sublists of 64K each and iterate over each sublist. Add abstract base class for various partition descriptors. Add logging messages in PruneScanRule for better debuggability. Address review comments. Close apache/drill#156