Add support for TINY/MEDIUM/LONGTEXT columns in MySQL

The column type is now selected based on the limit specified. This is done the Rails way. The limit must be specified in bytes. The limits are selected based on documentation here
http://dev.mysql.com/doc/refman/5.0/en/string-type-overview.html

If this is okay I can add support for TINYINT as well.
I fully understand the reasoning, but unless these values are constants, you are effectively forcing me to look up these values each time I need to use them. By "seemingly" random, I mean that the values are not easy to remember, unless you have powers of 1024 memorized by heart. How do you explain to someone that "65536" means "mediumtext" without going into unnecessary detail?