add a license in composer.json; MIT that is.
introduce given method in Sql as well, to start Where object.
do not evaluate simple string as callable (function names, such as 'system', is callable).
evaluate as closure, not callable which can be a string of a function name.
pass dbType from a main query to the sub-queries.
accept IN clause with sub-query.
update and insert statement can use alias for table name.
Revert "update and insert statement can use alias for table name."

This reverts commit 81bed3525de300bae4bc5572206adfb825ae4879.
renamed method, col, to given; to use the same method name as in Query/Sql class.
trying to remove DB class... use same subQuery method name as DB class.
trying not to use DB class...
removed Factory class and its usage.
give up removing DB; use it as simple factory class.
add classes for Pagination. A simpler version compared to that of ScoreDB.