Due to the complexity of this change, everything is documented in WL#3565

This patch is the third iteration, it takes into account the comments
received to date.


mysql-test/r/func_math.result:
  Improved test coverage
mysql-test/r/view.result:
  Name collision, x() is a geometry native in function
mysql-test/t/func_math.test:
  Improved test coverage
mysql-test/t/view.test:
  Name collision, x() is a geometry native in function
sql/item_create.cc:
  Revised the create_func implementation
sql/item_create.h:
  Revised the create_func implementation
sql/item_geofunc.h:
  Explicit Item allocation in the thread memory pool.
sql/lex.h:
  Removed function parsing from the lexical parser
sql/lex_symbol.h:
  Removed function parsing from the lexical parser
sql/mysql_priv.h:
  Server initialization and shutdown
sql/mysqld.cc:
  Server initialization and shutdown
sql/share/errmsg.txt:
  New error messages
sql/sql_yacc.yy:
  Removed function parsing from the lexical parser
tests/mysql_client_test.c:
  Spaces are no longer significant for function calls
mysql-test/include/parser_bug21114.inc:
  New tests
mysql-test/r/parser.result:
  New tests
mysql-test/r/parser_bug21114_innodb.result:
  New tests
mysql-test/t/parser.test:
  New tests
mysql-test/t/parser_bug21114_innodb.test:
  New tests