Cluster: from 4096 to 16384 hash slots.
Cluster: redis-trib updated to use 16384 hash slots.
Cluster: Initialize ip and port in createClusterNode().
Cluster: the cluster state structure is now heap allocated.
Cluster: move cluster config file out of config state.

This makes us able to avoid allocating the cluster state structure if
cluster is not enabled, but still we can handle the configuration
directive that sets the cluster config filename.
Cluster: with 16384 slots we need bigger buffers.
redis-cli: update prompt on cluster redirection.
Top comment for getNodeByQuery() improved.
Remove wrong decrRefCount() from getNodeByQuery().

This fixes issue #607.
Cluster: make valgrind happy initializing all the bytes of the node IP.
Removed useless newlines from hashTypeCurrentObject().
Cluster: sanity checks on the cluster bus message length.
Merge branch 'unstable' of github.com:antirez/redis into unstable
Cluster: specific error code for cluster down condition.
redis-trib: make a few comments 80-cols friendly.
Cluster: I/O errors are now logged at DEBUG level.
redis-trib: set the migrating slot in the correct way when resharding.
Cluster: ASKING command fixed, state was not retained.
Cluster: new command flag forcing implicit ASKING.

Also using this new flag the RESTORE-ASKING command was implemented that
will be used by MIGRATE.
Use RESTORE-ASKING for MIGRATE when in cluster mode.