Fix handling of associative arrays in PHP's var_export (#399)
Fix handling of associative arrays in PHP's var_export (#399)

* Fix handling of associative arrays in PHP's var_export

In PHP when you use `var_export` on associative array all string keys are inside single quotes. Currently all keys in this function are returned without single quotes around them. This commit fixes this issue.

Example of PHP's behaviour:
```
$array = [
    'username' => 'simivar',
];
```

it produces string with key in single quotes like:

```
array(
  'username' => 'simivar'
)
```

* Fix lint issues and add bugfixed header

kvz/phpjs,kvz/phpjs,kvz/phpjs,kvz/phpjs