Bugfixes

Hi,

these bug occur when using Magento 1.7.

[BUGFIX] Setting property _controller to false. Exception 'Mage_Core_Exception' with message 'Invalid block type: Mage_Adminhtml_Block_Empty_Edit_Form'

[BUGFIX] Zendesk_Zendesk_Block_Adminhtml_Create_Edit::getBackUrl() should be compatible with Mage_Adminhtml_Block_Widget_Form_Container::getBackUrl()

Also added a composer.json file.

Thanks for merging!

Cyrill