Store the impl pointer for ClassImpl after the name in the zend_class_entry on php5.3

Turns out the apache reload issue from f57607d2d58f6e7689a3550c84ba68ce42c6a7b3 was
never actually fixed. This commit however does finally fix it. The previously comment
trick however is still used with php 5.4 and php 5.5 as this 'new' trick doesn't work
with these versions of php as char* name in the zend_class_entry is a const char* and
is no longer internally copied and all (meaning we can't realloc it).