server selection rewrite

Fixes #447 (closed)

What is left to be done now (summary of the discussions below):

• fix or remove world_cz_lidovky_www.rpl and world_mx_nic_www.rpl
  • after that, remove verbose logging of rplan push/pop!
• review and change logging in the whole MR (to be consistent, configurable and apt)
• address the discussions about forwarding
• refactor the information retrieval and choice filtering in iter_choose_transport
• take a closer look at respdiff's results
• fix typos, clean up history

bench/bench_lru.c

@@ -11,7 +11,7 @@
 
 #include "contrib/ucw/lib.h"
 #include "daemon/engine.h"
-#include "lib/nsrep.h"
+#include "lib/selection.h"
 
 typedef kr_nsrep_lru_t lru_bench_t;