Final version of patch.
Adds support for specifying of DEFAULT NOW() and/or ON UPDATE NOW()
clauses for TIMESTAMP field definition.
Current implementation allows only one such field per table and
uses several unireg types for storing info about this properties of
field. It should be replaced with better implementation when new
.frm format is introduced.
BINARY(N) and VARBIBARY(N)
2. More 4.0 compatibility and more BINARY keyword consistency:
2a. CREATE TABLE a (a CHAR(N) BINARY)
is now synonym for
CREATE TABLE a (a CHAR(N) COLLATE xxxx_bin)
2b. SELECT BINARY x
is still synonin for
SELECT x COLLATE xxxxx_bin.
