letConst update: let/const undefined initial value

scope:
- hasFunctionScopeBetween
- hasLoopScopeBetween

core:
- getGlobalVariable
+ hasNodeBetween

letConst:
* renameDeclarations
letConst update: let/const undefined initial value: tests
+Symbol to jshint vars
classes transpiler: non-literal super

classes:
* superclass expression
* super inside constructor function
* static not-a-constructor method with "constructor" name

core:
* $nodeBegin and $bubbleNext properties in node for __getNodeBegin
function
core/is:
+ isExpression
core/standardVars:
* fix for-if problem
classes transpiler: non-literal super: tests