MEDIUM: cache: configuration parsing and initialization

Parse a configuration section "cache" and a http-{response,request}
actions.

Example:

    listen frt
        mode http
        http-response cache-store foobar
        http-request cache-use foobar

    cache foobar
        total-max-size 4   # size in megabytes
diff --git a/include/types/cache.h b/include/types/cache.h
new file mode 100644
index 0000000..b7e6e58
--- /dev/null
+++ b/include/types/cache.h
@@ -0,0 +1,13 @@
+#ifndef _TYPES_CACHE_H
+#define _TYPES_CACHE_H
+
+struct cache_obj {
+	int exp;   /* expire time */
+	int etag;  /* e-tag entry */
+	int last;  /* last entry */
+	void *buf;  /* ptr to buffer */
+}
+
+#endif /*_TYPES_CACHE_H */
+
+