Adding support for varcache-purge and opcache-purge
Bugfix: Adapting to tills naming scheme
Bugfix: Missed one function rename
changed all public functions to return ints

- 0 == success, non-0 == failure
- apcu_clear_cache always returns true, so that isn't even checked
  (see https://github.com/krakjoe/apcu/blob/61639af67447244746bc4bacd9619d67c6fe9ee8/php_apc.c#L438)
Merge pull request #3 from rwos/t/prime-varcache

prime varcache