Fix arrow operator precedence

I accidentially added => as the highest-precedence operator...
Fixed possible read after end of buffer and use after free.
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Fixed possible read after end of buffer and use after free.
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Fixed possible read after end of buffer and use after free.
Merge branch 'PHP-5.6'

* PHP-5.6:
  Fixed possible read after end of buffer and use after free.
Fixed day_of_week function as it could sometimes return negative values internally.
Merge branch 'day-of-week-issues' into PHP-5.5
Merge branch 'PHP-5.5' into PHP-5.6
Merge branch 'PHP-5.6'
Move checks for references into slow paths of handlers or helpers. Remove duplicate opcode handlers.
Fixed typo
Improved ASSIGN_DIM and ASSIGN_OBJ
Move checks for references into slow paths.
Pass znode_op structure by value (it fits into one word) instead of pointer to structure.
Move ZVAL_DEREF() and make_real_object() into slow paths.
simplified code
drop dead/unused code
Improved ASSIGN_<OP>, ASSIGN_DIM and UNSET_DIM
Wrap RETURN_VALUE_USED() with EXPECTED() or UNEXPECTED() macros according to more frequent usage patterns.
Improved basic zval copying primitives: ZVAL_COPY_VALUE(), ZVAL_COPY(), ZVAL_DUP()