Use open_normal_and_derived_tables instead of open_and_lock_tables when reading metadata for a table.
Add two test cases, one for "USE database" and one for "SHOW COLUMNS FROM table"
- Added testcases to test delimiters in 5.0
- In 5.0 it's allowed to have a up to 16 byte string as delimiter, everything after the delimiter token will be treated as the delimiter. It's even allowed to set delimiter to 'delimiter', ':;' or'MySQL'