More trigger/compound stmt support:
+ show triggers like x was mistakenly implemented as searching over trigger names.  Instead it should
  search over table names.  This has been fixed.
+ trigger bodies can use forward declared tables (as in a mysqldump file).  arrange for bodies to
  be parsed during declaration with resolution off.  this changes the stored body in the catalog.
+ Add parsing/emitting support for case statements, which are different than case expressions.
+ Add emitting support for compound statement lists (begin ... end).
+ Start building out compound statement infrastructure.
+ The view planner incorrectly swapped in the view def for all table instances of the matching
  view table.  Fix this to swap in only for the table instance being swapped out.  This caused
  one of the mysqldump infoschema queries to fail - added a test for that query.
+ If the definer in a trigger/view def is not known, use the current user instead.