A lightweight C interface for memcache servers. Use this when libmemcache is
overkill.

Basic design:

* public
enum memcache_return_t { RETURN_FAILURE = -1, RETURN_SUCCESS, ... }
enum memcache_return_t memcache_connect(const char* path_to_socket);
enum memcache_return_t memcache_reconnect(void);

enum memcache_return_t memcache_get(const char *key);
enum memcache_return_t memcache_del(const char *key);
enum memcache_return_t memcache_set(const char *key,
                                    void *data, size_t data_size,
                                    time_t expiration, short int flags);
enum memcache_return_t memcache_replace(const char *key,
                                        void *data, size_t data_size,
                                        time_t expiration, short int flags);
enum memcache_return_t memcache_flush_all(time_t when);
enum memcache_return_t memcache_stats(void);
enum memcache_return_t memcache_quit(void);



* private
enum memcache_return_t key_is_safe(char **key);
char *key_sanitize(const char *key);