Add .gitignore
Remove pipe outputs, add column names to output
Fix column existence checking and subquery recursion
Add sortedness checks and sorting before joins
Use the same fixtures in Query and Table tests
Add test for table sortedness checking method
Make Table's {column: idx} to use zero-based index, add column header construction test
Refactor: make left and right Tables members of Query
Lowercase column names, fix main program
Fix column reorder by replacing cut with awk
Add comments and rename some variables (cosmetic)
Add support for splat wildcards in selects