::class feature added
- Added function to handle ::class to compiler, added keyword handling to parser
- Altered the FETCH_CONST opcode handler (zend_vm_def.h) to return runtime lookups for static::class parent::class in non-static-compile situations

::class feature
Added phpt covering successful non-E_ERROR use cases

::class feature
- Added tests for E_ERROR conditions
- Made logic in zend_compile.c more clear
- Simplified zval assignment for class name lookup in zend_vm_def.h

::class feature
- removed 'check_namespace' from zend_do_resolve_class_name as check_namespace is always 1 when doing a RT lookup via zend_do_fetch_constant

::class feature
- Added additional tests for compile-time working scenarios in both method signatures as well as constant assignment