Improved empty string handling. Now ZE uses an interned string instead of allocation new empty string each time. (Some extensions might need to be fixed using str_efree() instead of efree() to support interned strings).
Merge branch 'PHP-5.6'

* PHP-5.6:
  Improved empty string handling. Now ZE uses an interned string instead of allocation new empty string each time. (Some extensions might need to be fixed using str_efree() instead of efree() to support interned strings).

Conflicts:
	NEWS
	Zend/zend_extensions.h
	Zend/zend_modules.h