EZC: style cleanup

* Rename camel-case files to lower case, per convention
* Put custom classes and functions into the HPHP namespace, instead of
  randomly distributed between HPHP and the root namespace
* Use tl_ prefix for variables defined with __thread, per convention
* Put local helper RL() in an anonymous namespace
* Rename ZendRequestLocalList to ZendRequestLocalVector, and fix
  related uses of the word "list" to mean "vector". The terminology was
  probably borrowed from zend_list.c, but even zend_list.c names its
  storage type "HashTable". Perhaps EG(regular_list) was initially
  implemented as a linked list, but later was migrated to a HashTable.
  There's certainly no rationale for allowing the misnomer to leak into
  zend_objects_API.cpp.
* Move zend_handle_cpp_exception() to anonymous namespace. It is an
  HHVM-specific helper.
* In ezc_test, replace multiple skipif files with config.skipif
EZC: implement free_storage and clone handlers

* Move object bucket store to its own class
* Implement storage of dtor/clone etc. function pointers as in Zend, instead
  of just storing a single void*
* Call free_storage and clone handlers as appropriate
* Make m_handle match the handle type in the Zend headers
* Fix singleton style in ZendExceptionStore to allow getInstance() to be
  inlined
* Add tests
* Add php_printf(), required by tests