function getNode( hash, v ) {
	var node = hash.first();
	while ( node ) {
		// Each node value should be a two-element array: [ value, count ]
		if ( node.value[ 0 ] === v ) {
			return node;
		}
		node = node.next;
	}
	return null;
}
Finds a node in a linked list hash based on a provided value.

@private
@param {LinkedList} hash - linked list hash
@param {*} v - value to find
@returns {(Node|null)} hash node or null