develop
Check if debug logger is enabled
Convert some for loops to foreach
Allow to specify simple expressions in FROM block
Create Core module, move main classes there
Fix select order
Decouple Commands module from Execution module
Improve key conditions support for between operator
Replace CommandHandler by IFuncUnit
Fix CTE parse with subselect
Fix inner join bug on CTE
Fix bug with stdout output with NULLs
Move more messages to resources
Add test classes, refactor EnumerableRowsInput
Add "except" keyword for "select" command
Move some messages to resources
Initial implementation of object selector