Add delete command

    * Specify one record id
    * TODO: list of record ids
    * Added to rtree status count of elemens in rtree

	modified:   apps/rtree_client/src/rtree_client.erl
	modified:   apps/rtree_server/src/rtree.erl
	modified:   apps/rtree_server/src/rtree_server.erl
Read filter function from input file.