Fixes PHP Fatal error: Cannot use Underscore\Types\String as String

[kenorb]

Fixes: #96

The error happens in PHP 7.x

E.g.

PHP Fatal error: Cannot use Underscore\Types\String as String because 'String' is a special class name in vendor/radic/tmp-underscore-php/src/Methods/StringMethods.php on line 5

Ignore the CI tests, as they're basically broken. My attempt to fix them is in #102.

[dustingraham]

Note, this is a bad patch. The problem does not exist in this version. Notice the name of the class is "Strings" which is fine.

The problem exists in older versions of anahkiasen/underscore-php where it is simply "String"

The request from the other ticket was to tag the 1.x branch with the fix.