Cleanup:  Changed procedure type from a int/char to an enum for easier to manage and debug code.

mysql-test/r/trigger.result:
  Test that mysql.proc is not used as part of creating or using a trigger.
mysql-test/t/trigger.test:
  Test that mysql.proc is not used as part of creating or using a trigger.
sql/sp.cc:
  The main bug fix is to not look up triggers in mysql.proc; This is done by ignoreing type == TYPE_ENUM_TRIGGER in sp_add_used_routine()
  Cleanup:  Changed procedure type from a int/char to an enum.
sql/sp.h:
  Cleanup:  Changed procedure type from a int/char to an enum.
sql/sp_head.h:
  Cleanup:  Changed procedure type from a int/char to an enum.
sql/sql_db.cc:
  Fix include order
sql/sql_lex.cc:
  Fix include order
sql/sql_parse.cc:
  Cleanup:  Changed procedure type from a int/char to an enum.
sql/sql_show.cc:
  Fix include order
sql/sql_view.cc:
  Fix include order