* README
version 0.7.13-1: build script fix
unicode transpiler update: bugfix: \u{x} can be escaped
quasiLiterals transpiler update: refactoring & bugfixing

* more accurate escaping
* more accurate linebreaks handling
* fix bug with tagged string template and linebreaks
local esprima update: 'save strict mode status' option

option name is 'strictMode'
need this information for static analyzer
classes transpiler update: ClassExpression & 'use strict' & more

classes:
+ added support for ClassExpression
+ class 'prototype' in not configurable/writable
* more accurate "use strict" handling (based on esprima node.strictMode
property)
- remove 'return' for default constructor (ES6 draft 5 april 2014
(Rev23): Reverted default for missing class constructor back to
“constructor(...args) {super(...args)} because of bug 2491)

core:
+ added support for ClassExpression

es6-transpiler.js:
+ strictMode=true options for esprima
destructuring transpiler update

* remove unnessesary '(' and ')'
* more accurate line breaks handling
* more accurate empty destructuring handling
function transpiler update:
* more accurate empty destructuring handling
forOf transpiler update: Symbol.iterator support