Move value and valueText out of tokens.
Use properties for 'kind' so that we can move nodes over to be just data objects.

Note: we still compute the kind for lists and tokens using accessors so that there is no additional
overhead for those common syntax constructs.
Move away from accessors.  They're not currently supported in cscript.
Move away from accessors.
Move away from accessors.
Move away from accessors.
Update LKG.
Don't compile with ES5 mode.
Start emitting node metadata in preparation for removing nodes.
Provide new childCount/childAt function that will replace the existing methods.
Pull childAt and childCount out of SyntaxElement and into functions.
Move Slim down childAt and childCount.
Update LKG.
Emit node metadata in syntaxkind order.
Remove last method from syntax nodes.
Move previousToken/nextToken to be functions instead of methods.
Explicitly provide a data property on syntax elements.
Move away from classes for nodes.
Create specialized node creation functions.  It's too slow to call setParentForChildren.
Update LKG.