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
Re-organize servenv flags a bit.

Flags are not enabled by default any more, but default
flags are very easy to enable. Next I will re-do the Port one.
query service: minor tweak in shutdown.

RowcacheInvalidator should be shut down before SchemaInfo. Otherwise,
it may lead to false invalidation alarms due to its inability
to find tables in the schema. This also conforms to the rule
that Close should be done in reverse order of Open.
Merge branch 'master' into parser
parser: select_expr -> SelectExpr
parser: drop obsolete fake tokens

SELECT_STAR & NO_DISTINCT
Merge branch 'replication'
Second part of servenv rework.

lameduckMode flag is not local (not used anywhere else).
Allowing default flags and non-default flags to be used.
Always using default flags in our applications.
Merge branch 'master' into replication
Doc changes: README, contributing, separate file for vttablet.
parser: Fix bug in parenthesized table_expression