Add dev dependency on HyperSQL
Handle 'raw' SQL in 'else' case of join-op-to-sql

This allows (select :* :from (raw "[raw tbl name]"))
Use ',' as the default join operation

For example:
 (select :* (from :t1 :t2 :t3)) => SELECT * FROM t1, t2, t3;
Use #"regexp" to quote a column or table name

Modify name-to-sql to treat regular expressions as quoted table
or column names.

Refactor expr-to-sql* and join-src-to-sql to use name-to-sql
instead of duplicating cases.