Begin adding support for triggers:
+ Add parse support for compound statements
+ Add parse support for create trigger
+ Add catalog entity for triggers
+ Add tschema class for triggers

Also, added a little test to verify storage gen scale down works correctly, and reorganized the parser
files slightly so that the MySQL.g file does not refer to rules in the PE.g file.
More trigger ddl support:
+ add support for show triggers
+ add support for show create trigger
+ add support for information_schema.triggers

Store the original raw sql alongside the body so that we can handle show create trigger.
Add a list of triggers into UserTable, make sure we maintain the collection appropriately.
Add PECreateTriggerStatement, make it persist PETable as the root and invalidate PETable.
Add a bunch of necessary fields to triggers (i.e. connection charset/collation, sql_mode, etc)
Make any stmt fail that would cause a trigger to fire.
Add a catalog upgrade to introduce the triggers table.
Other misc fixes:
+ Use a distinct enum type for trigger events
+ Restructure how triggers are stored in PETable for easy access later
+ Make PETriggers be subobjects of PETable (remove edges between triggers
  and the target table)
+ Require DMLStatements to indicate which trigger event type they are
Merge branch 'master' into kanzaros_cta

Conflicts:
	tesora-dve-core/src/main/java/com/tesora/dve/sql/expression/ScopeEntry.java
Add parsing support for NEW.<col> and OLD.<col> by introducing
a new TableInstance subclass with fixed aliases.
Merge branch 'master' of git@github.com:Tesora/tesora-dve-pub.git into petmal