Front-end support for LIMIT ROWS DELETE statements

The first commit you have already seen here on GitHub.  The second completes the ticket by doing error checking, planning the statement, and logging the explained plan:
* The HSQL parser stores the text of the DELETE statement in the VoltXML that it generates
* `DDLCompiler` generates VoltXML from the text of the DELETE statement to verify that the statement is a DELETE that targets the correct table
  * The statement is then saved in the catalog as a child of the Table 
* After `VoltCompiler` compiles stored procedures, it proceeds to compile any DELETE statements designed to help enforce the ROW LIMIT constraint
  * It's at this time that the explained plan is logged.
I MAY be wrong, but I expect HSQL to normalize this table attribute value to be the name of the table AS DEFINED vs. as referenced in the statement, so I would expect ".equals" to do just fine here, quoted ids or not. Since (I hope) we don't plan to support tables that differ in case only, I guess ignoring case is just a slihtly slower way to get to the same place. A historical note: there was one innovation week where Xin got a surprising performance boost just by replacing a pervasive pattern of needless case-insensitive comparisons with simple equals in and around catalog code.