parser: COMMENT_LIST -> Comments
parser: DISTINCT -> Distinct
parser: select_expression_list -> SelectExpressions
parser: SelectExpressions -> SelectExprs
parser: SQLNode abstraction

Intercoversion support between ast and newast is getting
out of hand. Instead, I'm going to allow Nodes to also
contain newast nodes as their subnodes.
parser: Node.Sub: *Node -> SQLNode
Merge branch 'master' into parser
Fix typo in analyzer.go
Merge branch 'master' into parser
Merge branch 'master' into parser
Merge branch 'master' into parser