Validators: added isPhpIdentifier()
Json: error Invalid UTF-8 sequence is detectable since PHP 5.3.1, removed workaround
Json: added support for future error messages
Json: own error handler is required only in PHP < 5.5
added marker interface Nette\Utils\IHtmlString for objects that will be not escaped by Latte. (BC break)

BC break: Nette\Templating\ITemplate is not implementing IHtmlString, so it is now escaped. It should be not problem since Nette 0.9.x.
__toString: when is called as method, exceptions are thrown
MimeTypeDetector: used FILEINFO_MIME_TYPE
added testing support files
added composer.json