[development] Drop MySQL 3 support

[Gerhard Killesreiter]

Hi there!

MySQL AB (the company behind our most used database) has announced a 
change in support options for their database products.

http://www.mysql.com/company/legal/mysql_lifecycle_policy.pdf

According to this document, the active support for MySQL 3.23 will end 
at the last of this month (ie on two weeks) and the extended support 
will end on the end of this year.

I therefore propose that we formally drop support of MySQL 3 as of 
Drupal 4.8 which will appear later this year.

MySQl 4.0's active support will end the last of September, we could 
consider dropping support for it too. Extended support will run until 
the end of 2008.

Dropping both MySQL 3 and 4.0 would enable us to rewrite some parts of 
our SQL queries. The extend of this would need to be researched.

I know that people will argue with "but there are so many ISPs that 
still run 3.23". ISPs that still run 3.23 after it has been retired by 
the supporting company are probably not worth the money you them.

Cheers,
	Gerhard