rcld: Add cl_utils cleanup procedure

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
rcld: Add support for nodes joining late
 * Support joining nodes when cluster is already working (i.e. there are
   active client states).
 * Add bitmap implementation.
 * Allow O(1) checks whether a element in vector is present.
 * Add bst_foreach function.
 * Implement copying client states to another node.
 * Store more information about buffers, programs and kernels.

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
rcld: Implement cl_release_{buffer,program,kernel} functions
 * Release all resources when quitting or expiring client state

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>