Add initial changelog for version 4.0

Merge branch '3.x'

Release PHP-Parser 3.1.1

Merge branch '3.x'

Conflicts:
lib/PhpParser/Builder/Trait_.php
test/PhpParser/Builder/TraitTest.php

Allow TraitUse statements in trait builder

Fixes #413.

Merge branch '3.x'

Handle Nop statement after brace-style namespace

Fixes #412.

Implement JsonDecoder

Converts JSON representation back into node tree.

Add strict_types to lib code

Add isSpecialClassName() method to Identifier and Name

Add toLowerString() method to Name and Identifier

Avoids patterns like strtolower((string) $name) when using
strict types.

[cs] apply short array to bin/php-parse

[cs] apply same to tests

[cs] spaces

[cs] use strict comparison where allowed

[cs] use PHP 5.4 short array, since PHP 7.0 is min version

[cs] remove unused imports

travis: add dash to make command format united (#407)

Prevents possible error when adding a second line

Docs: fix FAQ link anchor (#406)

Docs: Use PHP 7 return types (#405)

Fix missing semicolon in yacc grammar files (#403)

Merge branch '3.x'

Release PHP-Parser 3.1.0

Merge branch '3.x'

Remove deprecation of Name::$parts

It doesn't look like this is going away for now, and we currently
don't have the APIs to cover all existing usages elegantly.