Quote all SQL identifiers to retain the case.

[OndraZizka]

HSQLDB SQL identifiers are case sensitive, but also converted to upper case unless quoted in "...".

Case sensitivity rules for identifiers can be described simply as follows:
* all parts of SQL statements are converted to upper case before processing, except identifiers in double quotes and strings in single quotes
* identifiers, both unquoted and double quoted, are then treated as case-sensitive
* most database engines follow the same rule, except, in some respects, MySQL and MS SQLServer.

To retain the case, we would have to quote all uses of columns everywhere.

[OndraZizka]

Looks like this works in commit 0b62ca4 (which will likely become 2.1.0).